.engineering 

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Engineering 

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A  NEW  OIL-TESTING  MACII LXE  AND  SOME  OF  ITS  RESULTS.       143 


No.  959.* 

A    NEW  OIL- TESTING  MACHINE  AND   SOME   OF  ITS 

RESULTS.^ 

BY  ALBERT  KINOSBURY,   WORCESTER,   MASS. 

(Member  of  the  Society.) 

1.  IT  has  become  well  recognized  by  experimenters  that  there 
are  two  important  properties  of  lubricating  oils  and  greases  on 
which  their  value  depends — viscosity  and  body.     Viscosity  is  the 
property  by  virtue  of  which  the  lubricants  form  comparatively 
thick  films  between  rubbing  surfaces,  permitting  perfect  lubrica- 
tion, a  property  which  is  well  understood  and  capable  of  precise 
measurement.     Thurston  early  pointed  out  the  case  of  perfect 
lubrication  as  probably  capable  of  exact  mathematical  treatment,;}: 
and  Reynolds,  in  1886,  published  an  elaborate  analysis  of  such  a 
case,§  with  application  to  the  experiments  of  Beauchamp  Tower.  | 

2.  As  the  result  of  computations  from  Tower's  data,  Reynolds 
found  that  the  minimum  thickness  of  the  oil  film  and  the  difference 
of  the  radii  of  the  brass  and  the  journal  were  .000375  and  .00077 
inch  respectively,  the  load  being  100  pounds  per  square  inch  and 
the  diameter  of  the  journal  4  inches.    .In  1899  the  writer  experi- 
mented with  a  journal  3.82  inches  in  diameter  and  10  inches  long, 
bearings  and  journal  having  exactly  the  same  radius.     The  chords 

*  Presented  at  the  New  York  meeting  (December,  1902)  of  the  American  Society 
of  Mechanical  Engineers,  and  forming  part  of  Volume  XXIV.  of  the  Transactions. 

f  For  further  references  on  the  same  topic  see  Transactions  as  follows  :  ' 
No.  7,  vol.  i.,  p.  73  :  "Measurement  of  the  Friction  of  Lubricating  Oils."     0.  J. 

H.  Woodbury.  " 
No.  120,  .vol.  iv.,  p.  315:    "Economy  in  Lubrication  of  Machinery."     Geo.  N. 

Comly. 
No.  163,  vol.  vi.,  p.  136 :  "Measurements  of  Friction  of  Lubricating  Oils."     C.  J. 

H.  Woodbury. 
No.  173,   vol.  vi.,   p.   437:  "Valuation   of   Lubricants   by   Consumers."     R.  H. 

Thurston. 

No.  404,  vol.  xi.,  p.  1013  :  "  Durability  of  Lubricants."    J.  E.  Denton. 
No.  433,  vol.  xii.,  p.  405  :  "  Special  Experiments  with  Lubricants."    J.  E.  Denton. 
\  "  Friction  and  Lost  Work."     Wiley  &  Sons. 
§  "  Theory  of  Lubrication."     Phil.  Trans.,  1886. 
\  Proceedings  of  the  Inst.  Mechanical  Engineers,  1884. 

78814,5 


144:       A  NEW  OIL-TESTING  MACHINE  AND  SOME  OF  ITS  EESULTS. 

0f.  the  beaHii|f  Surfaces  were  3  inches  each,  the  speed  80  and  190 
revolutions  per  minute,  and  the  journal  was  flooded  with  machin- 
&?$  ^I'-'CB^infl^asurement  of  the  displacement  of  the  bearings 
the  oil  film  was  found  to  have  a  mean  thickness  of  from  .00021  to 
.00023  inch  under  loads  varying  from  27  to  270  pounds  per 
square  inch. 

3.  A  condition  essential  to  the  formation  of  such  films,  as  shown 
by  Reynolds,  is  that  the  rubbing  surfaces  should  have  a  very  slight 
inclination  to  each  other  in  the  direction  of  their  relative  motion. 
This  condition  is  generally  fulfilled  by  a  slight  difference  in  the 
radii  of  the  journal  and  the  bearing,  due  to  the  original  looseness 
of  fitting  or  to  wear.     When  the  loads  are  very  great  or  the  sur- 
faces irregular,  or  when  the  conditions  are  otherwise  such  as  to 
make  the  necessary  inclination  impossible,  it  is  well  known  that 
the  action  of  the  lubricant  is  imperfect  and  frequently  very  de- 
fective.    In  such  cases  the  theory  of  Reynolds,  which  so  clearly 
accords  with  experiment  for  the  conditions  of  perfect  lubrication, 
becomes  quite  inapplicable;  nor  has  any  theory  been  formed  which 
applies  to  these  imperfect  or  extreme  conditions.     Such  cases 
occur  in  pivots,  where  the  surfaces  are  necessarily  parallel,  in 
cylindrical  bearings  \vhich  are  too  closely  fitted,  in  any  portion  of 
any  bearing  surface  where  the  pressure  is  unduly  high,  and  in 
heavily  loaded  bearings  generally.     Under  any  of  these  circum- 
stances the  effect  of  the  lubricant  in  reducing  friction  depends 
mainly  upon  the  "  body  "  or  "  oiliness."     The  nature  of  this  prop- 
erty, or  combination  of  properties,  is  not  well  understood,  but  it 
appears  probable  that  it  is  an  intensified  viscosity  in  that  part  of 
the  fluid  within  the  region  of  attraction  of  the  surface  molecules 
of  the  metal. 

4.  One  of  the  most  frequent  causes  of  contradictory  results  in 
friction  tests  is  that  the  effects  of  viscosity  may  readily  mask  the 
effects  of  body,  and  another  cause  is  found  in  the  changes  in  the 
rubbing  surfaces  which  always  take  place  with  wear,  and  which 
must,  therefore,  accompany  any  test  for  body. 

In  any  well-fitted  journal  in  which  perfect  lubrication  exists, 
the  friction  is  determined  by  the  speed,  the  pressure,  and  the  vis- 
cosity of  the  oil.  Varying  any  one  of  these  factors  while  keep- 
ing the  others  constant,  there  is  some  value  of  the  variable  for 
which  the  coefficient  of  friction  is  a  minimum  *  and  which  at  the 

*  Tliurston  :  "Friction  and  Lost  Work,"  pp.  811,  326.  Woodbury  :  "Meas- 
urement of  Friction  of  Lubricating  Oils,"  Transactions  A.  S.  M.  E.,  vol.  vi.,  p.  151. 


A  NEW  OIL-TESTING  MACHINE  AND  SOME  OF  ITS  RESULTS.        145 


FIG.  33. 


10 


146        A  NEW  OIL-TESTIKG    MACHINE  AND  SOME  OF  ITS  KESULTS. 

same  time  marks  very  nearly  the  limit  of  the  variable  for  the 
condition  of  perfect  lubrication.  This  is  illustrated  by  the  curves 
plotted  in  Fig.  34,  representing  ((/sis  made  on  the  machine  de- 
scribed later.  In  tl<  s  the  load  and  the  speed  were  kept 
constant,  the  viscosity  of  the  oil  bring  varied  in  each  case  by 
varying  the  temperature.  For  each  of  the  three  oils,  the  mini- 
mum coefficient  of  friction  is  reached  at  a  temperature  of  about 
180  degrees  Fahr.,  with  the  given  speed  and  pressure.  As  the 


PEED    1 2O  REV.  =  43' FT.  M IN, 
ESSURE  34O  LBS.  &Q..IN. 


OLIVE  GIL 

VISCOLITE  (MltiERA  L)  OIL 


FIG.  34. 

temperature  varies  either  way  from  this  value,  the  coefficient  of 
friction  increases;  on  the  one  hand  increasing  with  the  viscosity 
of  the  oil,  the  metallic  surfaces  being  completely  separated  by  a 
measurably  thick  film;  on  the  other  hand  increasing  because  the 
decreased  viscosity  permits  the  surfaces  to  approach  so  that  some 
parts  of  the  nominal  bearing  areas  are  subjected  to  very  intense 
pressures,  up  to  the  limits  of  strength  or  plasticity  of  the  metals. 
It  is  in  these  localities  that  the  body  of  the  lubricant  determines 
to  some  extent  the  friction  and  the  wrear  of  the  journal,  the  vis- 
cosity being  also  effective  on  some  parts  of  the  area. 

5.  The  relations  of  the  coefficient  of  friction  to  the  other  vari- 
ables, in  a  journal  giving  results  as  plotted  in  Fig.  34,  may  be 
stated  as  follows : 


A  NEW  OIL-TESTING  MACHINE  AND  SOME  OF  ITS  RESULTS.       147 

infrpji«o  of  Where  the  viscosity  is  effective,          Where  the  body  is  effective, 

the  coefficient  of  friction  the  coefficient  of  friction 

Pressure Decreases,  Increases. 

Speed Increases.  Decreases. 

Temperature Decreases.  Increases. 

Viscosity Increases.  Decreases. 

Body Decreases. 

It  is  thus  seen  that  the  effects  of  body  and  of  viscosity  are  in 
nearly  all  respects  diametrically  opposite,  and  that  it  must  neces- 
sarily be  very  difficult  to  derive  reliable  information  regarding 
the  lubricating  values  of  oils  from  friction  tests  in  which  the 
effects  of  viscosity  and  those  of  body  are  not  separately  recogniz- 
able. Under  this  consideration,  methods  of  testing  which  are 
described  in  this  paper  are  arranged  with  special  reference  to  the 
conditions  under  which  the  effects  of  either  property  may  be  in- 
vestigated independently  of  the  effects  of  the  other.  The  appa- 
ratus used  is  serviceable  also  for  tests  under  any  intermediate 
condition. 

6.  Fig.  33  shows  the  general  appearance  of  the  testing  machine, 
for  the  frame  and  driving  parts  of  which  a  14-inch  drilling  ma- 
chine was  utilized.     The  test  journal  has  its  axis  vertical;  it  is 
suspended  from  the  spindle  by  means  of  a  flexible  coupling  and 
runs  between  two  opposed  bearings  in  a  cylindrical  cup  or  case, 
which  may  be  filled  with  the  oil  to  be  tested  if  a  a  bath  "  is  de- 
sired.    The  load  on  the  bearings  is  provided  by  means  of  a  helical 
spring  of  900  pounds  capacity,  with  screw  adjustment  and  with 
a  device  for  quick  application  or  removal  of  the  load  without  dis- 
turbing the  adjustment.     This  spring  is  enclosed  in  a  horizontal 
tube  attached  to  the  side  of  the  oil  case.     The  cup  has  a  cover 
with  a  small  hole  for  the  insertion  of  a  thermometer. 

7.  The  cup  and  attached  parts  are  borne  on  a  hollow  vertical 
spindle  If  inches  in  diameter,  turning  freely  in  a  sleeve  supported 
from  the  frame  of  the  machine ;  the  spindle  extends  about  two  feet 
below  the  sleeve  and  is  suspended  from  a  fixed  bracket  by  a  tem- 
pered steel  wire  passing  through  the  spindle  to  its  lower  end.     In 
testing,  these  suspended  parts  turn  freely  to  a  position  where  the 
torsion  of  the  suspension  wire  balances  the  friction  at  the  test 
journal,  and  the  angle  of  torsion,  which  may  be  as  great  as  270 
degrees,  is  read  from  a  graduated  disk.     The  suspended  parts 
being  counterbalanced,  there  is  no  appreciable  pressure  of  the 
spindle  against  its  sleeve ;  and  when  the  oil  in  this  bearing  becomes 
evenly  distributed,  there  is  no  error  from  friction,  as  has  been 


148         A  NEW  OIL-TESTIX*  E  AND  SOME  OF  ITS  RESULTS. 

amply  proven  by  tests  with  air"  optical  lever  "  as  well  as  by  the 
uniformity  of  the  results  in  use.  At  the  same  time,  the  viscosity 
of  the  oil  serves  the  purpose  of  damping  the  oscillations  which 
arise  from  variations  in  speed  or  friction  at  the  test  journal.  This 
mode  of  suspension  gives  large  indications  for  very  small  frictions 
at  the  test  journal,  while  a  helical  spring  placed  on  the  extension 
of  the  spindle  is  added  for  tests  involving  great  friction. 

8.  The  cup  and  the  test  journal  contained  in  it  may  be  heated 
as  desired  by  a  Bunsen  flame.     The  revolutions  of  the  journal  are 
indicated  by  a  counting  device,  not  shown  in  the  figure. 

9.  For  tests  involving  perfect  lubrication  (friction  due  to  vis- 
cosity only),  the  test  journal  used  is  If  inches  diameter,  of  tool 
steel,  hardened,  ground,  and  polished.     The  brasses  are  sectors 
cut  from  a  ring  finished  in  the  lathe,  each  having  an  arc  of  about 
120  degrees  and  a  length  of  2  inches.     These  brasses  are  fitted 
with  some  care,  so  that  when  perfectly  clean  they  may  be  made 
to  adhere  to  the  journal  after  the  manner  of  well-fitted  "  surface 
plates."     In  making  tests,  care  is  taken  to  prevent  wear  of  these 
parts,  which  are  used  only  under  such  loads  that  the  oil  film  effects 
complete  separation  of  the  surfaces  and  entirely  prevents  wear; 
the  load  is  always  relieved  before  starting  or  stopping  the  journal; 
and,  finally,  a  friction  device  in  the  driving  coupling  safeguards 
the  journal  from  motion  against  excessive  friction.     These  pre- 
cautions against  wear  are  necessary  to  insure  the  constancy  of 
results. 

10.  It  will  be  noted  that  the  above  conditions  are  not  such  as 
occur  in  practice;  but  it  should  also  be  noted  that  this  method  of 
testing  is  intended  to  show  the  effects  of  viscosity  in  lubricants  and 
not  the  varying  imperfection  of  any  particular  bearing  surfaces 
subjected  to  wear. 

11.  In  Figs.  34  to  37  are  shown  curves  plotted  from  tests  made 
with  the  test  journal  and  bearings  just  described,  a  bath  of  oil 
being  used  in  each  instance.    Figs.  34,  36,  and  37  show  the  effects 
of  variation  in  viscosity  upon  the  friction,  both  by  the  use  of  oils 
of  different  viscosities  and  by  the  variation  in  viscosity  due  to 
change  of  temperature.     In  Fig.  34,  the  lard  oil  and  the  olive  oil 
have  very  nearly  the  same  viscosity,  the  lard  oil  being  slightly 
more  viscous,  as  is  also  and  more  clearly  shown  in  Fig.  35;  the 
mineral  oil  (Fig.  34)  is  more  viscous  than  either  at  low  tempera- 
tures, but  less  at  high  temperatures  (see  also  Fig.  38).     Fig.  36 
shows  the  friction  of  four  cylinder  oils  with  varying  temperatures ; 


A  NEW  OIL-TESTING  MACHINE  AND  SOME  OF  ITS  RESULTS.       149 


Fig.  37,  four  engine  oils.  Fig.  38  shows  relations  of  friction,  speed, 
and  viscosity  for  five  oils  at  three  different  speeds ;  the  viscosity  was 
found  by  the  ordinary  and  rather  crude  pipette  method.  These 
curves,  although  relating  to  conditions  not  far  removed  from  the 
limit  of  capacity  of  the  journal,  approximately  verify  Reynolds' 
deduction  that  the  friction  is  proportional  to  the  viscosity  of  the 
oil,  and  they  also  show  the  friction  to  vary  roughly  as  the  square 
root  of  the  speed.  The  data  for*  Fig.  38  were  taken  from  average 
results  of  tests  made  in  the  laboratory  of  the  Worcester  Poly- 


FRICTION 
OF 


TE$T8 
3LS 

f.3', 


LARL 
OLIV 


COEFFICIENT  OF 

.063      .ok*      .ods      .o 


A  .  KlHi  iBURV 


ate      .on 


FIG.  35. 

technic  Institute,  by  members  of  the  class  of  1901;  the  degree  of 
certainty  attained  in  the  friction  tests  may  be  illustrated  by  the 
following  values  of  the  coefficient  of  friction  found  by  the  succes- 
sive experimenters,  no  corrections  being  made  for  variations  in 
speed  nor  for  errors  in  calibration  of  the  torsion  wire. 

COEFFICIENTS  OF  FRICTION  FOR  SPERM  OIL  ;  PRESSURE,  340  LBS.  SQ.  IN.    90°  FAHR. 


117  R.  P.  M. 

182  R.  P.  M. 

281  R.  P.  M. 

.000906 

.001171 

.00146 

.000915 
.000886 

.001158 
.001158 

.00155 
.00151 

.000915 

.001125 

150      A  NEW  OIL-TESTING  MACHINE  AND  SOME  OF  ITS  RESULTS. 


It  may  be  noted  that  the  lowest  coefficients  of  friction  shown 
in  Figs.  34,  36,  and  37  are  extremely  small,  and  the  writer  believes 
them  to  be  smaller  than  any  hitherto  recorded  for  lubrication 
maintained  solely  by  the  motion  of  the  journal.  The  minimum 
friction  is  but  one-fifth  of  that  of  the  best  ball  bearing,  as  far  as 


0018 


\ 


.0016 


\ 


\ 


\ 


\ 


$.0003 


Fa.hr. 


300 


FIG.  36. — FRICTION  TESTS  OF  CYLINDER  OILS. 
PRESSURE,  340  POUNDS  PER  SQUARE  INCH.     SPEED,  94  FEET  PER  MINUTE. 

tests  of  the  latter  have  been  recorded.  The  value  for  the  mini- 
mum coefficient  for  all  oils  tested  on  this  journal  has  been  found 
to  be  approximately  .0006,  whatever  the  speed,  pressure,  and  tem- 
perature by  which  the  minimum  coefficient  may  be  determined; 
the  oils  varying  from  "  spindle  "  to  "  cylinder/'  the  speeds  from 
42  to  101  feet  per  minute,  the  pressures  up  to  340  pounds  per 
square  inch  and  the  temperatures  up  to  340  degrees  Fahr.  Very 


A  NEW  OIL-TESTING  MACHINE  AND  SOME  OF  ITS  EESULTS.       151 

nearly  the  same  minimum  coefficient  was  found  in  the  writer's 
tests  *  of  a  journal  lubricated  by  air  only;  the  value  in  which  case 
was  .00075. 

12.  For  tests  for  comparing  oils  with  respect  to  body  or  oiliness, 


OOfO 


.000* 


FIG.  37. — FRICTION  TESTS  OF  ENGINE  OILS. 
PRESSURE,  170  POUNDS  PER  SQUARE  INCH.    SPEED,  94  FEET  PER  MINUTE. 

the  best  results  have  been  obtained  by  the  use  of  a  hardened  and 
polished  steel  journal  J  inch  in  diameter,  running  between  two 
brass  bearings  about  1  inch  long;  on  this  small  journal  pressures 
up  to  8,000  pounds  per  square  inch  may  be  applied  if  necessary. 
The  samples  of  oil  to  be  compared  are  contained  in  small  brass 

*  Journal  of  the  American  Society  Naval  Engineers,  1897. 


152       A  NEW  OIL-TESTING  MACHINE  AND  SOME  OF  ITS  RESULTS. 

cups  placed  inside  the  case  and  surrounding  the  test  journal,  each 
cup  having  a  wire  for  transferring  oil  to  the  journal;  the  case, 
samples,  and  journal  are  together  heated  to  any  desired  tempera- 
ture. 

13.  In  testing  for  body,  the  oils  are  compared  in  pairs,  being  ap- 
plied alternately  at  the  upper  end  of  the  bearing ;  one  being  applied 
until   the    friction  becomes    constant   or    nearly   so,    the    other 
is  then  applied  until  it  displaces  the  first,  and  again  the  friction 
becomes  constant  at  the  new  value;  this  process  is  repeated  several 
times.     The  oil  giving  the  less  friction  is  assumed  to  have  the 
greater  body.     In  this  way  the  order  of  the  body  values  of  six 
samples  of  oils  of  the  same  class  may  generally  be  determined  for 
any  given  temperature  in  an  hour  or  less;  the  friction  indications 
rapidly  follow  the  changes  of  the  oils  and  are  generally  quite  con- 
sistent.    When  the  oils  to  be  compared  are  of  different  classes  (as 
mineral  oils  with  fixed  oils),  the  first  friction  indications  on  chang- 
ing oils  are  frequently  misleading,  and  a  longer  time  is  required 
to  insure  certainty  of  results. 

14.  The  speeds  for  the  body  tests  are  made  rather  low  and  pres- 
sures not  unnecessarily  high,  in  order  to  avoid  heating  and  wear  of 
the  journal,  since  it  is  essential  for  comparative  purposes  that  the 
surfaces  should  be  in  the  same  condition  for  both  samples  compared 
— a  requisite  which  above  all  others  led  to  the  development  of  this 
method  of  testing.     Again,  the  actual  temperature  of  the  oil  at 
the  test  surfaces  is  shown  more  nearly  by  the  thermometer  if  but 
little  heating  by  friction  be  permitted.     The  writer  has  not  found 
the  order  of  body  values,  as  determined  by  this  method,  to  vary 
with  the  speed  or  the  pressure  within  a  considerable  range.     A 
speed  of  50  to  100  revolutions  (3  to  6  feet  per  minute),  with 
sufficient  pressure  to  make  the  coefficient  of  friction  only  as  great 
as  .01  to  .03,  have  been  found  most  satisfactory;  the  pressures 
being  from  500  to  5,000  pounds  per  square  inch,  according  to  the 
character  of  the  oils. 

15.  The  results  of  this  method  of  testing  for  body  agree  thor- 
oughly with  the  principal  fact  hitherto  established  with  regard 
to  body  as  distinguished  from  viscosity — namely,  that  the  mineral 
oils  as  a  class  have  much  less  body  than  the  animal  and  vegetable 
oils.     For  example,  in  a  body  test  of  mineral  oil  and  lard  oil 
having  viscosities  98.9  and  83.7  respectively  at  90  degrees  F.,  as 
determined  by  the  Dudley  pipette,  the  lard  oil,  although  the  less 
viscous,  gives  very  decided  evidence  of  greater  body,  by  its  much 


A  NEW  OIL-TESTING  MACHINE  AND  SOME  OF  ITS  EESULTS.       153 

smaller  friction.  On  the  other  hand,  certain  cylinder  oils,  wholly 
or  largely  mineral,  and  exceeding  lard  oil  greatly  in  viscosity  have 
also  greater  body  than  lard  oil. 

16.  The  method  of  testing  readily  indicates  differences  in  body 
in  samples  of  nominally  the  same  oil  from  different  manufac- 


.0024- 


.00*0 


H, 

Q 


0008 


.0004 


i  / 


-f°- 


/O 


SO       60        70 


9O       /9Q     //O 


zo      3c      4O 

Viscosity     by 

FIG.  38 — FRICTION,  VISCOSITY,  AND  SPEED. 
PRESSURE,  340  POUNDS  PER  SQUARE  INCH.    TEMPERATURE,  90  DEGREES  FAHR. 


154       A  NEW  OIL-TESTING  MACHINE  AND  SOME  OF  ITS  RESULTS. 


turers,  such  as  lard  oil;  change  of  body  in  a  given  fixed  oil  on 
exposure  to  the  air  for  some  time;  the  addition  of  small  propor- 
tions of  mineral  oil  to  animal  or  to  vegetable  oil,  or  vice  versa. 

17.  Among  the   specific  results   thus  far  obtained,   the   four 
cylinder  oils  whose  variations  of  viscosity  with  temperature  are 
shown  in  Fig.  36,  were  found  to  have  body  in  the  same  order  as 
viscosity;  the  body  being  tested  at  ISO  degrees  and  312  degrees 
Fahr.     Similar  results  were  found  for  the  oils  in  Fig.  37.     Again, 
samples  of  castor,  lard,  olive,  and  sperm  oils  were  placed  in  the 
order  named  by  the  body  test,  which  order  was  the  same  as  that 
of  their  viscosities.     It  thus  appears  that  body  is  in  some  way 
related  to  viscosity,  but  the  relation  must  be  quite  different  in  the 
mineral  oils  and  the  fixed  oils. 

18.  The  following  tables  of  observations  will  serve  to  show  the 
character  of  the  numerical  results  of  tests  made  in  this  way,  the 
oils  compared  being  in  the  first  case  two  samples  of  lard  oil,  and 
in  the  second  case  two  engine  oils,  Nos.  28  and  29  (see  Fig.  37  for 
viscosity  tests);  speed,  105  revolutions  per  minute  (6.9  feet  per 

minute) : 

BODY  TESTS  OP  WINTER  STRAINED  LAUD  OILS. 

Load,  300  Ibs.;  pressure  2,550.  Ibs.  sq.  in. 


Oil  No. 

Torsion,  Degrees. 

Coefficient  of  Friction. 

Temperature  Fahr. 

1 

33 

.0233 

72 

2 

25 

.0176 

1 

31 

.0218 

2 

24 

.0169 

1 

30.5 

.0215     . 

2 

23.5 

.0166 

1 

29  5 

.0208 

2 

23 

.0162 

72 

BODY  TESTS  OF  ENCINE  OILS. 


Oil  No. 

Torsion, 

Degrees. 

Coefficient  of  Friction. 

Temperature  Fahr. 

29 
28 
29 
28 


29 
28 
29 


Load,  200  Ibs.;  pressure,  1,700  Ibs.  sq.  in. 


11.5 
15 
11 
15 


.0124 
.0161 
.0118 
.0161 


Load,  100  Ibs.;  pressure,  850  Ibs.  sq.  in. 


8.5 

4.0 
5.0 
3.5 


.0182 
.0086 
.0107 
.0075 


69 
69 
69 
69 


120 
120 
120 
120 


A  NEW  OIL-TESTING  MACHINE  AND  SOME  OF  ITS  KESULTS.        155 

Thus,  while  the  coefficient  of  friction  is  not  always  constant 
for  any  one  oil,  the  one  effecting  the  greater  reduction  of  friction 
is  readily  distinguished,  and,  hence,  is  to  be  regarded  as  having 
the  greater  body.  This  appears  to  be  the  principal  use  which 
can  be  made  of  the  numerical  results,  since  the  mean  values  of  the 
coefficients  of  friction  are  not  characteristic  of  the  oils,  but  de- 
pend also  upon  the  varying  degree  of  roughness  of  the  surfaces, 
the  loads,  the  speeds,  the  temperatures,  and  the  kinds  of  metals 
forming  the  journal  and  the  bearing.  Nevertheless,  great  or 
small  differences  in  the  values  of  the  coefficients  of  friction  must 
be  taken  as  indicating  correspondingly  great  or  small  differences 
in  body. 

DISCUSSION. 

Prof.  R.II.  Thurston. — Professor  Kingsbury's  paper  impresses 
me  as  being  a  very,  exceptionally  valuable  contribution  to  the 
literature  of  its  subject.  The  results  of  his  investigation,  as  illus- 
trated by  the  diagrams  presented,  have  this  very  important  pecul- 
iarity:  that  they  exhibit,  as,  I  think,  never  has  been  done  before, 
the  laws  of  variation  of  frictional  resistance  when  the  lubricant  is 
maintained  in  an  invariable  state,  and  in  such  manner  as  to  show 
precisely  what  are  the  effects  upon  thoroughly  lubricated  sur- 
faces, of  simple  change  of  temperature  and  of  simple  variation  of 
pressure,  uncomplicated  by  variations  of  condition  of  the  metal 
surfaces  between  which  the  lubricants  are  placed.  These  curves 
are  the  most  complete  and  the  smoothest,  on  the  whole,  that  I 
have  yet  met  with,  with  perhaps  the  single  exception  of  some  of 
those  of  Woodbury,  representing  his  experiments  on  the  mineral 
oils.*  These  later  tests,  however,  have  greater  range,  and  are 
also,  in  part,  outside  the  limit  of  the  earlier  work.  These  extraor- 
dinarily low  coefficients,  also  would  seem  to  indicate  a  more 
perfect  attainment  of  the  condition  of  maximum  effectiveness  of 
lubrication — complete  separation  of  the  metals,  the  film  of  oil 
being  maintained  intact  throughout.  In  all  earlier  experiments, 
we  find  evidence  of  more  or  less  metallic  contact  and  rubbing  at 
some  stage  of  the  experiment,  converting  fluid  into  solid  friction 
and  introducing  a  change  of  the  law  of  variation,  thus  giving 
curves  of  correspondingly  varying  law.  Such  changes  of  con- 

*  "Friction  and  Lost  Work  in  Machinery  and  Mill  Work,"  R.  H.  Thurston, 
New  York,  J.  Wiley  &  Sons  ;  London,  Chapman  &  Hall. 


156       A  NEW  OIL-TESTING  MACHINE  AND  SOME  OF  ITS  RESULTS. 

dition  may  be  found  illustrated  in  ample  extent  and  variety  in 
work  published  by  me  when  pioneering  in  this  field.* 

The  point  of  minimum  friction,  to  which  I  then  called  atten- 
tion, is  better  exhibited  in  Fig.  3±  of  the  paper  than  in  any  of  my 
curves  ;  while  the  latter  seem  to  indicate  that  this  critical  tem- 
perature of  maximum  effectiveness  of  the  lubricant  is  approxi- 
mated in  a  variety  of  oils,  organic  as  well  as  inorganic.  But  it 
is  to  be  noted  that  journals  in  ordinary  work  do  not  usually 
attain  that  temperature  and  that  the  difference  among  the  oils 
increase  as  the  temperature  is  lower,  at  least  within  the  allow- 
able range,  f  The  minimum  coefficient  reported  in  these  experi- 
ments is  the  lowest  with  which  I  have  met,  and  may  perhaps  be 
accepted  as  that  to  which  perfect  lubrication  approximates  as  the 
condition  of  the  journal  and  the  system  of  lubrication  approxi- 
mates perfection. 

The  very  closely  hyperbolic  form  of  these  curves  is  another 
very  interesting  result  of  this  work.  It  follows  that,  since  the 
product  of  the  coefficient  of  friction  and  the  pressure  is,  under 
such  circumstances,  practically  constant,  the  total  frictional 
resistance,  under  similarly  perfect  conditions,  is  unaffected  by 
change  of  load  on  the  journal.  This  is  one  of  those  phenomena 
which  conspire  to  make  the  friction  of  the  steam  engine  constant 
for  all  loads,  as  I  showed  by  direct  experiment  many  years  ago, 
in  the  case,  particularly,  of  the  non-condensing  engine.^ 

Professor  Kingsbury's*  oil-testing  machine  is  a  very  ingenious 
and  remarkably  refined  piece  of  scientific  apparatus,  and  seems 
especially  suited  to  such  peculiarly  fine  work  of  investigation  as 
is  here  illustrated.  The  difficulties  of  determining  the  effect  of 
varying  temperature  in  this  case  can  only  be  fully  understood  by 
those  who  have  attempted  such  researches,  and  they  seem  to  be, 
by  this  apparatus,  admirably  disposed  of.  It  brings  out,  as 
never  was  done  before,  the  differences  between  "  viscosity  "  and 
what  its  inventor  calls  "body,"  a  quality  which  remains  to  be 
defined. 

In  illustration  of  the  correspondences  and  the  differences  be- 
tween the  work  of  which  the  paper  is  descriptive,  and  that  which 
is  ordinarily  performed  by  the  standard  methods  and  ordinarily 
satisfactory  apparatus  of  the  laboratory  in  commercial  investiga- 

*  Ibidem.  f  Ibidem. 

\  "  Manual  of  the  Steam  Engine,"  vol.  ii.,  chap,  v.,  §§  132-136. 


A  NEW  OIL-TESTING  MACHINE  AND  SOME  OF  ITS  RESULTS.       157 


A1ISO03IA 


158       A  NEW  OIL-TESTING  MACHINE  AND  SOME  OF  ITS  EESULTS. 

tions  for  practical  purposes,  we  may  compare  the  diagrams  of 
the  paper  with  those  of  Figs.  39-41.  These  are  not  presented  as 
representing  an  effort  to  secure  such  refinement  as  would  charac- 
terize the  more  deliberate  and  minutely  studied  work  of  research, 
either  in  experimentation  or  deduction,  but  simply  as  bringing 
out  the  more  clearly  the  difference  between  ordinary  tests  and 
those  here  discussed,  in  which  every  effort  is  made,  and  success- 
fully, to  insure  that  the  results  shall  not  be  complicated  by  the 
presence  of  more  than  the  one  variable,  the  law  of  which  is 


PRESSURE  ON  JOURNAL.       POUNDS  PER  SQUARE  INCH  Tturston 

FIG.  40. 


sought  to  be  determined.  The  correspondences  are  evident  on 
inspection,  and  it  is  interesting  to  see  that  the  commerical  work 
admirably  sustains  the  deductions  from  the  research. 

Fig.  39  represents  the  variation  of  viscosity  with  temperature 
in  comparisons  of  the  characteristics  of  four  distinctly  different 
oils  :  No.  1,  an  oils  old  in  the  market  as  a  "  cylinder  oil"  ;  No. 
2,  a  " crusher  oil"  ;  No.  3,  an  " engine  oil,"  and  No.  4,  a  mod- 
erate-priced "  machine  oil. " 

Fig.  40  is  a  comparison  of  these  oils  to  ascertain  their  normal 
temperatures  of  steady  operation  under  varying  pressures. 

Fig.  41  exhibits  their  relative  and  absolute  friction-reducing 
values  at  various  pressures. 

It  is  seen  that  the  variation  of  viscosity,  determined  in  the 
usual  manner,  as  temperatures  change,  follow  the  same  general 
law,  and  the  higher  the  grade,  as  rated  for  the  market,  the 
greater  the  viscosity,  except  that  Nos.  3  and  4  are  transposed, 
indicating,  possibly,  that  No.  3  is  incorrectly  rated  and  that  its 


A  NEW  OIL-TESTING  MACHINE  AND   SOME   OF  ITS  RESULTS.  "U9 


* 


••••••••-'*  !!HL'i?'!52!  »»K«£» 


" 


••••"•••••••'••»•  • 


160     A   NEW   OIL-TESTING   MACHINE   AND   SOME   OF  ITS   RESULTS. 

purchaser  would  secure  a  better  bargain  in  buying  No.  4; 
although  the  latter  assumes  a  higher  position  on  the  diagram  of 
temperature  variation  than  No.  3.  It  is  also  to  be  noted  that 
the  line  for  variation  of  temperature  with  pressure  is  a  straight 
line  which  does  not  pass  through  the  origin,  and  this  would  seem 
to  be  another  corroboration  of  Professor  Kingsbury's  remarks 
regarding  the  existence  of  at  least  two  distinct  properties,  deter- 
mining the  work  of  friction.  It  is  probable  that  the  friction  - 
reducing  property  and  the  conductivity,  or  the  convection  of  the 
oil,  or  both  the  latter  properties  acting  in  conjunction,  may  give 
rise  to  the  differences  here  referred  to.  The  friction-pressure 
diagram  shows  correspondence  with  the  results  given  by  the 
author  of  the  paper  under  discussion,  in  the  apparently  hyper- 
bolic character  of  the  curves  for  the  several  oils,  while  also 
showing  that  the  curve  varies  more  or  less  from  the  line  of  the 
equilateral  hyperbola  when  the  quality  of  the  bearing  and  the 
state  of  the  rubbing  surfaces  affect  results,  as  they  practically 
always  do  in  the  ordinary  tests. 


1074  THE   BURNING -OF   TOWN   REFUSE. 


No.  1O4§.* 

THE  BURN  IN  0  OF  TOWN  REFUSE, 

WITH  SPECIAL  REFERENCE  TO   THE  DESTRUCTORS   AT  BRUSSELS, 
WEST  HARTLEPOOL,   MOSS  SIDE,    AND   WESTMINSTER, 

BY  GEORGE  WATSON,  LEEDS,   ENGLAND. 

Member,  Institution  of  Mechanical  Engineers. 

1.  Refuse  in  Great  Britain. — Town  refuse  in  Great  Britain 
varies  considerably  in  character  according  to  local  conditions,  but 
it  is  a  fairly  safe  generalization  to  say  that  it  consists  of  one-third 
by  weight  of  water,  one-third  combustible  matter,  and  one-third 
incombustible.     The  last  is  withdrawn  at  the  end  of  the  burning 
process  in  the  form  of  hard  clinker. 

The  combustible  material  is  largely  vegetable  and  putrescible 
matter,  but  it  includes,  in  the  United  Kingdom,  varying  quantities 
of  unburned  cinder  from  the  wasteful  open  fires  so  dear  to  the 
English  people  in  more  senses  than  one.  This  cinder  is  much  more 
plentiful  in  winter  than  in  summer. 

2.  Continental  Refuse. — Cinder  is  almost  entirely  absent  from 
town  refuse  on  the  Continent  of  Europe,  where  closed  stoves  are 
used,  producing  a  fine  incombustible  ash.     The  author  has  fre- 
quently proposed  that  the  fine  ash,  which  requires  no  treatment, 
should  be  collected  in  separate  bins  in  each  house,  and  not  taken 
to  the  destructor  at  all. 

3.  Collection. — The  nature  of  the  material  is  affected  largely  by 
method  of  collection,  which  varies  greatly  in  different  towns.    For 
instance,  in  Edinburgh  there  is  a  daily  collection,  the  inhabitants 
being  obliged  to  place  their  refuse  on  the  street  in  receptacles 
which  they  provide  themselves.    These  receptacles  are  usually  any- 
thing but  effective,  and  the  contents  are  spread  about  by  the  wind 
and  the  rag-pickers,  and  mixed  with  the  street  sand ;  sometimes  the 
same  cart  collects  both  street  sweepings  and  refuse.    The  result  is 

*  Presented  at  the  Chicago  meeting.  May  and  June  1904,  of  the  American 
Society  of  Mechanical  Engineers,  and  forming  part  of  Volume  XXV,  of  the 
Transactions. 


THE   BURNING  OF   TOWN   REFUSE.  1075 

a  very  light  sandy  material,  difficult  to  burn,  which  measures  no 
less  than  80  cubic  feet  to  the  ton. 

In  Bradford,  Leeds  and  Sheffield,  on  the  other  hand,  many  large 
ash-pits  are  used,  in  some  cases  combined' with  privies,  and  they 
are  only  cleaned  out  at  intervals  of  weeks  or  months.  At  one 
destructor  in  Bradford  the  refuse  contains  40  per  cent,  of  night- 
soil.  Under  such  conditions  the  refuse  is  wet  and  heavy,  meas- 
uring only  40  cubic  feet  to  the  ton. 

In  the  author's  opinion  the  prevailing  custom  of  reckoning  the 
amount  of  refuse  burned  by  weight  is  misleading,  and  better  com- 
parisons as  to  the  labor  involved  would  be  got  by  reckoning  in 
cubic  yards.  It  is  obvious  that  a  ton  of  bulky  refuse  requires 
much  more  labor  in  handling  than  a  ton  of  such  wet  and  heavy 
stuff  as  is  collected  at  Bradford. 

4.  Refuse  as  Fuel. — Town  muck  is  so  heterogeneous  that  it  is 
almost  impossible  to  compare  it  with  other  fuels  by  any  of  the 
ordinary  methods,  and,  in  particular,  calorimeter  tests  have  always 
seemed  to  the  author  to  be  quite  futile.    It  would  appear  imprac- 
ticable to  obtain  a  fair  sample  small  enough  to  go  into  a  calorimeter 
of  a  material  comprising  garbage,  vegetable  refuse,  dust,  straw, 
paper,  rags,  bones,  broken  glass,  tin  cans,  wood,  cinders,  sacks,  old 
boots,  buckets,  water-cans,  casks,  carpets  and  huge  rolls  of  kamp- 
tulicon,  to  say  nothing  of  the  carcases  of  cattle,  dogs,  cats  and  pigs, 
the  last  being  sometimes  brought  in  numbers  after  an  outbreak 
of  swine  fever.    Amongst  the  articles  gravely  registered  as  having 
been  destroyed  at  one  of  the  early  Leeds  destructors  was  "  one  sea- 
serpent."    In  two  instances  parcels  of  explosives  have  found  their 
way  into  furnaces,  and  blown  out  the  fronts,  fortunately  without 
causing  bodily  injury  in  either  case.     To  state  the  nature  of  the 
miscellaneous   rubbish  comprised  in  the  refuse   of  towns  is  to 
demonstrate  at  once  its  unsuitability  for  agricultural  manure,  and 
the  danger  of  allowing  it  to  accumulate. 

5.  Refuse  as  Manure. — ~No  farmer  cares  to  cover  his  fields  with 
broken  glass  and  tin  cans,  and  in  the  few  instances,  such  as  at 
Manchester  and  Glasgow,  where  some  of  the  rubbish  is  taken  by 
farmers,  it  has  to  be  first  sorted  and  ground,  and  then  transported 
long  distances  free  of  charge  by  the  Corporation  at  a  cost  exceed- 
ing that  of  destruction  by  fire. 

6.  Danger  to  Health. — Accumulations  of  this  material  involve 
the  twofold  danger  of  lowered  vitality  owing  to  an  impure  atmos- 
phere, and  direct  propagation  of  disease  through  poisonous  germs 

69 


1076  THE   BURNING  OF   TOWN   REFUSE. 

carried  by  flies,  rats,  dust  particles,  running  water  and  other 
agencies.  Refuse  heaps  also  frequently  occasion  great  nuisance 
and  expense  by  spontaneous  combustion.  "  Destruction  "  of  refuse 
is  a  somewhat  scientific  term,  but  it  serves  to  distinguish  the 
method  of  disposal  by  fire  from  the  reduction  or  digestion  processes 
used  in  the  United  States  for  recovery  of  grease  and  other  matters, 
and  from  the  slower  process  of  nature,  involved  in  disposal  by 
dumping,  which  have  been  sometimes  referred  to  as  the  "  method 
of  putrefaction/7 

The  author  does  not  propose  to  go  through  the  history  of 
destructors  in  Great  Britain,  where  they  originated.  The  late  Mr. 
Alfred  Fryer,  of  Nottingham,  was  the  pioneer,  and  built  his  first 
successful  destructor  in  1875.  It  may  be  thought  that  nearly 
thirty  years  is  a  long  time  for  the  development  which  has  taken 
place  to  have  occupied.  It  must  be  remembered,  however,  that 
being  dependent  upon  municipal  enterprise,  rapid  advance  has 
only  been  possible  in  recent  years. 

The  author  regrets  to  say  that,  in  spite  of  the  demonstrations 
made  many  years  ago  of  the  danger  of  filling  old  pits  and  hollows 
with  this  material,  the  practice  of  doing  so,  and  of  afterwards 
erecting  dwelling  houses  upon  it,  has  prevailed  in  most  towns  and 
cities  in  spite  of  all  sanitary  considerations,  and  has  only  given 
way  to  the  use  of  destructors  when  every  pit  and  hollow  within  the 
municipal  boundary  has  been  filled. 

In  passing  over  the  history  of  the  development  of  destructors, 
the  author  is  also  obliged  to  omit  reference  to  many  types  which 
have  proved  successful,  and  have  served  to  advance  the  general 
practice,  and  to  many  names  honorably  associated  with  such 
advance;  and  in  dealing  later  with  the  details  of  certain  installa- 
tions has  thought  it  best  to  confine  himself  strictly  to  his  own 
experience.  He  will  therefore  deal  only  with  plants  on  one  par- 
ticular system;  at  the  same  time  remarking  that  there  are  many 
other  destructors  of  different  types  in  use  which  reflect  the  greatest 
credit  on  all  concerned. 

7.  Natural  Draught. — The  earlier  destructors  were  all  upon  the 
natural-draught  system,  with  slow  combustion,  low  temperatures, 
and  little  or  no  provision  for  raising  steam.  In  charging  and 
clinkering  the  furnaces  large  doors  were  kept  open  for  about  one- 
third  of  the  time,  and  the  strong  chimney  draught  above  the  grates 
necessarily  drew  in  tons  of  cold  air  over  the  fire  through 
such  openings,  making  high  furnace-heats  impossible.  Frequent 


THE  BURNING  OF   TOWN   REFUSE.  1077 

complaints  of  nuisances  from  the  chimney  shafts  caused  by  stinks 
and  dust  resulted. 

8.  Fume    Cremators. — Fume    cremators,    introduced    by    Mr. 
Jones,  the  borough  engineer  of  Baling,  were  added  in  many  cases, 
consisting  of  secondary  fires  in  the  flues  fed  with  coal  or  coke,  over 
which  the  products   of  combustion  had  to  pass,  thus  scorching 
them  and  largely  obviating  the  nuisance.     These  fume  cremators 
certainly  rendered  a  continuance  of  working  possible  in  many 
cases,  but  owing  to  the  high  cost  for  fuel  they  were  not  always 
regularly  worked. 

9.  Maintenance. — One  advantage  of  natural  draught  and  low 
temperatures  was  that  the  brickwork  was  easily  maintained,  and 
furnaces  of  the  most  ordinary  construction  have  been  found  to 
last  fifteen  or  sixteen  years  without  much  expense  in  renewing  the 
fire-brick  linings.     Even  to-day  engineers  are  found  who  advocate 
low  temperatures  on  this  account. 

10.  High  Temperatures. — Modern  plants  working  at  high  tem- 
peratures with   forced  draught,   and  with   steam-raising  as  one 
of  the  most  important  objects,  involve  much  more  difficult  prob- 
lems as  regards  construction  and  maintenance,  and  also  as  regards 
the  protection  of  the  stokers  from  heat  and  back-draught.     No 
ironwork  can  last  long  in  a  modern  destructor  unless  cooled  in 
some  special  manner,  and  contrivances  such  as  dampers  within 
the  furnace  for  closing  or  partly  closing  the  draught  outlet  when 
the  furnace  door  is  opened,  have  become  not  only  superfluous  but 
impracticable.     The  author  has  learned  to  look  with  the  greatest 
distrust  upon  any  supposed  improvement  involving  the  introduc- 
tion of  unprotected  ironwork  into  the  hot  furnaces  or  flues. 

11.  8  tor  age   of  Heat. — In  high-temperature  furnaces  heat  is 
stored  in  the  brickwork  to  such  an  extent  that  the  furnace  arch 
hardly  ceases  to  glow  even  when  nearly  a  ton  of  cold  refuse  has 
been  freshly  charged,  and  consequently  the  temperature  does  not 
fall  below  the  point,  say  1,250  degrees  Fahr.,  at  which  septic 
gases  might  be  given  off. 

12.  Plenum   System. — No   one   has   contributed   more   to   the 
attainment  of  such  temperatures  than  Mr.  William  Horsfall,  of 
Leeds,   who  first  introduced  the  plenum  system  and  the  front 
exhaust  flue^    Recognizing  that  the  principal  cause  of  low  tempera- 
tures in  the  old  natural-draught  furnaces  was  the  inrush  of  a  large 
excess  of  cold  air  over  the  fire  during  the  lengthy  processes  of 
charging  and  clinkering,  he  set  himself  to  apply  forced  draught 


1078  THE  BURNING  OF  TOWN  REFUSE. 

on  the  closed  ash-pit  system,  first  by  means  of  fans  and  later 
by  steam  blast,  and  this  enabled  him  to  choke  the  furnace  outlet 
in  such  a  manner  as  to  always  maintain  a  slight  pressure  above  the 
atmosphere  within  the  furnace,  thus  absolutely  preventing  the 
admission  of  cold  air  when  the  furnace  doors  were  open  and  allow- 
ing loose  fitting  doors  to  be  used. 

13.  Front  Exhaust. — He  placed  his  exhaust  flue  in  the  front 
portion   of  the  furnace   arch,   thus   reversing  the   draught   and 
bringing  all  the  fumes  given  off  by  the  refuse  drying  on  the 
hearth  over  the  hot  fire  and  "  cremating  "  them  effectually  within 
the  furnace  itself. 

14.  Steam  Raising. — An  important  result  of  the  introduction 
of  high-temperature  destructors  has  been  that  town  refuse  has 
now  come  to  be  regarded  in  some  quarters  as  fuel.     When  it  is 
remembered  that  the  combustible  matter  in  the  charge  is,  say, 
only  one-third  by  weight  of  the  whole,  the  claims  which  have  been 
put  forward  of  a  commercial  evaporation  of  three  pounds   of 
water  to  high-pressure  steam  per  pound  of  muck  can  only  be 
regarded   as   ridiculous,   for  they  would  place  the   combustible 
portion  of  the  material  on  a  level  with  best  Welsh  coal.     It  is  to 
be  regretted  that  inventors  have  come  forward  from  time  to  time 
offerings  guarantees  of  such  results  in  regular  working.      Their 
claims  can  only  be  accounted  for  by  their  lack  of  experience. 
Failure  in  the  fulfilment  of  such  guarantees  under  contract  have 
led  to  a  serious  reaction,  and  there  is  now  a  tendency  to  discredit 
altogether  the  possibility  of  steam-raising  from  town  refuse.     As 
usual  the  truth  is  found  between  the  two  extremes. 

15.  Steam  as  a  By-Product. — The  great  value  of  steam  as  a  by- 
product of  a  destructor  plant  designed  primarily  for  the  disposal 
of  the  muck  (but  well  arranged  for  the  production  and  utilization 
of  the  steam)  has  been  amply  demonstrated.     It  may  now  be  laid 
down  with  perfect  confidence  that,  on  an  average,  town  refuse  in 
Great  Britain  may  be  expected  to  evaporate  in  every-day  working 
its  own  weight  of  water  from  and  at  212  degrees  Fahr.     In  many 
places  it  is  safe  to  guarantee  1  pound  of  steam  per  1  pound  of 
refuse  in  summer  and  1|  pounds  in  winter.     As  much  as   1.5 
pounds  may  be  got  on  test  with  careful  management,  as  will  be 
seen  in  the  record  of  a  test  at  West  Hartlepool,  given  in  Ap- 
pendix 1. 

The  value  of  the  refuse  as  fuel  varies  considerably  in  different 
districts,  and  according  to  the  season  and  the  amount  of  coal  used 


THE  BURNING   OF   TOWN   REFUSE.  1079 

by  each  household.  In  some  colliery  districts  the  miners  are  pro- 
vided with  coal  free  of  charge,  and,  as  might  be  expected,  the 
best  steam-raising  refuse  is  to  be  met  with  there. 

On  the  other  hand,  the  author  has  had  experience  of  seaside 
towns,  such  as  Lowestoft  and  Ramsgate,  where  in  hot  weather 
hardly  any  coal  fires  are  found  (gas-stoves  being  used  for  cooking) ; 
and  the  refuse  consists  largely  of  garden  rubbish,  garbage,  and 
bad  fish — poor  stuff  for  steam-raising. 

In  wood-burning  countries,  and  where  closed  stoves  are  used, 
not  only  does  the  absence  of  cinder  mean  a  very  poor  fuel,  but  the 
fine  ash  (if  collected  with  the  refuse)  has  a  tendency  to  surround 
and  choke  such  combustibles  as  may  be  present,  and  to  put  out  the 
fire  altogether. 

16.  Refuse  Auto-Combustible. — Nevertheless,  the  author  has 
had,  up  to  the  present  time,  no  experience  of  town  refuse  which 
was  not  auto-combustible,  except  that  from  the  eastern  district 
(the  poorest  part)  of  Berlin.  Even  there  he  has  by  no  means 
given  up  the  problem  of  burning  the  refuse  by  itself.  Monte 
Carlo  and  Pernambuco  are  places  where  little  or  no  cinder  is 
found  in  the  muck,  and  yet  destructors  are  in  successful  operation 
at  each  of  these  without  the  addition  of  other  fuel. 

IT.  High  Pressures  of  Steam. — To  revert  to  the  conditions  pre- 
vailing in  Great  Britain,  it  used  to  be  said  that  high  pressures  of 
steam  could  not  be  obtained  from  the  heat  of  destructors ;  but  a 
consideration  of  the  temperature  of  the  gases  leaving  the  destruc- 
tor, which  varies  from  1,700  degrees  Fahr.  to  2,000  degrees  Fahr., 
might  have  shown  the  fallacy.  As  a  matter  of  fact,  steam  is  being 
obtained  at  Accrington  (with  a  "  Lancashire  "  boiler)  and  Moss 
Side,  Manchester  (with  "  Water-Tube  "  boilers),  at  200  pounds 
per  square  inch,  while  pressures  of  120  pounds  per  square  inch  are 
now  quite  common. 

The  conditions  for  the  best  working  in  the  destruction  of  refuse 
are  identical  with  those  required  for  efficient  steam-raising;  and 
with  high  temperatures  the  clinker  is  harder,  the  working  more 
rapid,  and  the  chimney  clearer  of  smoke. 

18.  Arrangement  of  Cells  and  Boilers. — The  grouping  of  the 
cells  and  boilers  is  an  important  and  much  debated  subject.  Many 
early  designers,  attaching  great  importance  to  the  radiations  from 
the  burning  mass,  held  that  the  heating  surfaces  of  the  boiler 
should  be  immediately  over  the  fire,  and  as  close  to  it  as  possible. 
It  is  almost  needless  to  say  that  the  results  were  disappointing, 


1080  THE  BURNING  OF   TOWN   REFUSE. 

as  the  temperature  necessary  for  complete  combustion  was  never 
reached  at  all,  owing  to  the  cooling  effect  of  the  surfaces  of  the 
boiler. 

Later  developments  of  the  same  idea  are  still  in  evidence  in  the 
"  sandwiching  "  of  boilers  and  cells,  that  is,  the  placing  of  a  cell  on 
each  side  of  a  single  boiler  and  delivering  the  products  of  com- 
bustion through  side  openings  in  the  cells  directly  below  the  boiler 
tubes.  This  plan  is  much  more  satisfactory  than  the  earlier  one; 
but  the  chief  drawback  to  its  adoption  is  that  when  either  of  the 
cells  is  newly  charged,  and  the  gases  may  be  escaping  at  a  tem- 
perature below  what  is  necessary  for  complete  combustion,  they 
may  come  into  contact  with  the  cool  surfaces  of  the  boiler  un- 
consumed,  and  so  pass  away  to  the  chimney,  while  fluctuations  of 
steam  pressure  may  also  occur. 

In  the  author's  opinion,  the  best  grouping  of  cells  and  boilers  is 
to  arrange  the  cells  in  blocks  or  batteries  not  exceeding  six  or 
eight  in  number,  and  to  place  the  boiler  or  boilers  as  near  as 
\  possible  to  the  block  of  cells. 

In  the  case  of  the  back-to-back  cells,  arranged  in  such  a  block 
with  the  main  flue  underneath  them,  there  is  little  or  no  loss  by 
radiation,  as  the  main  flue  is  surrounded  by  cells.  At  the  same 
time  the  immense  advantage  is  secured  that  the  products  of  com- 
bustion from  all  the  cells  are  thoroughly  mixed  in  the  red-hot  flue 
before  passing  to  the  boiler,  and  thus  if  one  of  the  cells  happens  to 
be  somewhat  cooler  than  the  rest,  any  unburned  gases  that  may 
escape  from  it  are  thoroughly  burned  in  the  main  flue,  where 
there  is  always  some  excess  of  air.  All  the  heat  generated  in  the 
cells  is  carried  forward  by  the  hot  gases,  except  the  small  propor- 
tion which  escapes  by  radiation  from  the  outer  surfaces  of  the 
furnaces  themselves. 

With  batteries  of  cells  in  a  single  row,  Fig.  515,  it  is  also  possible 
to  arrange  that  the  loss  by  radiation  shall  be  small.  A  further 
advantage  is  that  the  cells,  being  close  together,  the  stokers  have 
less  floor  space  to  work  over,  and  the  arrangement  of  railways  or 
conveyors  for  removal  of  clinkers  is  simpler  than  with  boilers  and 
cells  alternately. 

19.  Working  in  Rotation. — "Under  good  management  the  work- 
ing of  the  cells  is  kept  strictly  in  rotation,  a  time-table  and  a  clock 
being  provided,  and  good  time-keeping  in  charging  and  clinkering 
being  insisted  upon. 

20.  Constant  Pressure  of  Steam. — With  such  methods  the  tern- 


THE   BURNING   OF   TOWN   REFUSE. 


1081 


perature  of  the  gases  entering  the  boilers  may  be  maintained 
almost  constant,   and  the  old  complaint  of  the  steam  pressure 


fluctuating  disappears  entirely.  The  clinkering  and  charging  of 
each  cell  takes  place  every  one  and  a  half  to  two  hours,  according 
to  the  nature  of  the  material.  In  some  cases  clinkering  every  hour 


1082  THE   BURNING   OF   TOWN   REFUSE. 

has  been  tried,  but  the  experience  of  the  author  is  that  a  longer 
run  gives  a  harder  clinker,  and  a  better  result  all  round,  any 
small  loss  of  steaming  power  being  more  than  compensated  by 
reduced  labor  and  more  perfect  combustion.  The  capacity  per 
cell  depends  mainly  upon  the  grate  area,  and  the  strength  of  blast, 
but  also,  of  course,  very  greatly  upon  the  attention  of  the  firemen. 

21.  Blast. — With  refuse  for  fuel  it  is  extraordinary  how  soon 
a  high-pressure  blast  blows  the  fires  into  holes.     With  forced 
draught  on  the  closed  ash-pit  system,  a  few  minutes'  use  of  the 
rake  to  fill  up  the  blowholes  will  increase  the  draught  gauge 
from  one-quarter  inch  to  over  an  inch  of  water  column.    In  some 
cases  a  draught  of  as  much  as  2  inches  is  used,  but  there  are  two 
great  disadvantages  to  such  pressures :  first,  that  much  more  labor 
is  required  (almost  constant  trimming  of  the  fires  being  necessary 
to  fill  the  blow-holes),  and,  second,  that  the  high  blast  sends  up 
quantities  of  hot  dust  and  sparks,  which  cake  on  the  roof  of  the 
furnace  and  in  the  flues,  necessitating  constant  cleaning. 

22.  Grate  Area. — From  25  to  30  square  feet  of  grate  area 
has  usually  been  provided  in  each  cell  up  to  recent  years;  but,  of 
late,  cells  having  42  square  feet  of  grate  area  have  become  com- 
mon; and  also  much  smaller  cells  are  being  introduced  for  special 
purposes,  such  as  for  use  in  hospitals,  asylums  and  factories.    For 
plants  up  to  four  cells  furnaces  of  30  square  feet  of  grate  area  are 
most  suitable ;  but  for  larger  plants  furnaces  of  42  square  feet  are 
preferable,  as  the  use  of  larger  cells  reduces  the  cost  of  labor. 
The  length  of  the  grate  is  usually  6  feet  from  back  to  front  in 
both  sizes  of  cells.    It  is  customary  to  work  throughout  the  twenty- 
four  hours  for  six  days  a  week ;  but  in  some  cases,  where  steam  is 
only  required  for  night  work,  such  as  in  electric  lighting,  the 
hours  of  working  have  been  reduced,  and  the  number  of  cells 
and  boilers   correspondingly  increased.     It  is   quite  possible  to 
bank  the  fires  for  twenty-four  hours,  and  even  longer,  so  that  they 
do  not  require  relighting  on  a  Monday  morning. 

For  the  purpose  of  illustrating  his  remarks,  the  author  h"as  pro- 
vided drawings  and  photographs  showing  several  different  types 
of  plant  in  connection  with  the  construction  of  which  he  has 
recently  been  employed.  The  installations  chosen  for  this  purpose 
are  those  at  Brussels  (twenty-four  cells,  Fig.  516),  West  Hartle- 
pool  (twelve  cells,  Fig.  517"),  Moss  Side,  Manchester  (six  cells, 
Fig.  518  and  Fig.  519),  and  Westminster  (six  cells,  Fig.  520  and 
Figs.  521  and  522).  Each  of  these  destructors  is  placed  in  a 


THE  BURNING   OF   TOWN   REFUSE. 


1083 


FIG.  516.— DESTRUCTOR  OP  24  CELLS. 
Grate  area,  30  sq.  feet  each.    City  of  Brussels. 


1084 


THE   BURNING   OF   TOWN    REFUSE. 


'Watson  (ieo.  Am.Bank  Note  Co.,N.Y. 

-   FIG.  517.— DESTRUCTOR  OF  12  CELLS. 
Grate  area  of  30  sq.  ft.  each.    Corporation  of  West  Hartlepool. 


THE   BURNING   OF   TOWN   REFUSE. 


1085 


densely  populated  district,  and  all  are  in  full  operation  without 
causing  any  inconvenience  or  complaint, 

23.  Destructors  at  Brussels  and  West  Hartlepool. — The  Brussels 
and  West  Hartlepool  furnaces,  Figs.  516  and  517,  are  of  the  back- 
to-back  type,  fed  by  hand  through  holes  in  the  deck  on  the  top  of 
the  furnaces.  These  feed  holes  are  of  somewhat  peculiar  construc- 


Dustcatchers 


Chimney 


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Mens'  Rooms  Below 


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FIG.  518. — DESTRUCTOR  OF  6  CELLS. 

Grate  area  of  30  eq.  ft.    Moss  Side,  Manchester. 

tion ;  they  are  so  designed  that  no  lid  is  required,  the  refuse  itself 
being  trodden  down  into  the  holes  to  stop  them  up.  It  will  readily 
be  seen  that  the  use  of  a  lid  on  a  deck  littered  with  rubbish  would 
be  very  inconvenient.  In  order  that  the  method  of  stopping  above 
referred  to  may  be  used,  there  is  provided  immediately  below 
the  feed-hole  (which  is  common  to  two  furnaces)  a  flat  table  or 
saddle  so  arranged  that  when  refuse  is  dragged  or  shovelled  into 
the  hole  and  allowed  to  lie  on  the  saddle  it  fills  up  and  chokes  the 
opening.  When  it  is  desired  to  charge  either  furnace  the  refuse 


1086 


THE   BURNING   OF    TOWN    REFUSE. 


is  simply  pushed  off  the  saddle  with   a  prong — a  very  simple 
operation,  requiring  very  little  labor. 

The  deck  is  6  feet  below  the  level  of  the  tipping  floor,  thus 
forming  a  convenient  bunker  for  the  reception  and  storage  of  the 
muck  as  near  as  possible  to  the  feed-holes.  In  the  West  Hartlepool 
plant  the  deck  is  formed  of  steel  plate  separated  from  the  top  of 
the  furnace  by  an  air  space  in  order  that  it  may  be  kept  cool;, 
while  at  Brussels  the  deck  is  carried  entirely  by  the  furnaces  and 
is  formed  of  reinforced  concrete.  At  West  Hartlepool  the  refuse 
is  carted  up  an  inclined  way  with  a  gradient  of  one  in  twenty, 


FIG.  519.— FURNACES.    6-CELL  PLANT.    Moss  SIDE. 

while  at  Brussels  there  are  two  electric  overhead  travelling  cranes, 
one  over  each  group  of  twelve  cells,  which  lift  the  cart-bodies  off 
the  wheels  and  dump  their  contents  on  to  the  decks.  The  latter 
system  has  also  been  adopted  at  Hamburg,  and  in  the  plant  now 
being  completed  at  Zurich. 

24.  Moss  Side  Destructor. — At  Moss  Side,  as  will  be  seen  on 
reference  to  the  drawing,  Tig.  518  and  Fig.  519,  the  six  cells 
are  arranged  side  by  side  in  a  single  battery  with  the  two  water- 
tube  boilers  at  the  end  of  the  battery,  the  charging  openings  are 
at  the  back  of  the  furnaces,  and  are  provided  with  suitable  furnace- 
doors.  These  doors  are  now  generally  planed  to  fit  their  frames, 
and  are  lined  with  fire-bricks.  They  are  raised  and  lowered  by 
levers  and  balance  weights,  and  give  a  good  command  of  the 
furnaces,  which  slope  downwards  to  the  front. 

The  refuse  is  tipped  from  the  carts  into  a  bunker  of  concrete, 
and  having  a  sloping  back,  so  that  the  toe  of  the  heap  of  refuse  is 


THE   BURNING   OF   TOWN   REFUSE. 


1087 


never  far  from  the  surface  mouth,  into  which  it  is  thrown  by  a 
shovel.  This  method  would  seem  at  first  sight  to  involve  more 
labor  than  the  top  feeding,  but  it  is  found  in  practice  that,  while 
it  costs  more  to  put  in  the  muck  with  a  shovel,  the  labor  in  front 
of  the  furnace  in  dragging  forward  and  trimming  is  correspond- 


V. ...?.. ..9 


10 


20  Feet 


FIG.  520. — DESTRUCTOR  OF  6  CELLS. 

Grate  area  of  42  sq.  ft.  each.    City  of  Westminster. 

ingly  lessened.  It  may  be  remarked,  however,  that  even  at  West 
Hartlepool,  where  the  refuse  is  not  bulky,  the  labor  of  charging 
costs  one-third  of  the  stokers'  wages,  and  it  is,  therefore,  a  matter 
of  the  utmost  importance  to  reduce  it  as  much  as  possible. 

25.  Westminster  Destructor. — The  Westminster  Destructor, 
shown  in  Fig.  520  and  Figs.  521  and  522,  has  been  erected  on 
the  Shot  Tower  Wharf,  at  the  south  side  of  Waterloo  Bridge,  in 
the  center  of  the  metropolis,  and  serves  a  district  of  which  Covent 
Garden  Market  and  the  Strand  form  important  features.  The 


1088  THE   BURNING   OF   TOWN   REFUSE. 

refuse  is  exceedingly  bulky,  consisting  largely  of  market  and  shop 
refuse,  paper,  packings,  straw,  and  all  kinds  of  light  material, 
measuring  not  less  than  90  cubic  feet  to  the  ton.  To  feed  such 
stuff  by  means  of  a  shovel  would  be  very  costly,  and  therefore 
special  means  were  demanded.  The  conditions  have  been  met  by 
a  new  design  of  furnace,  into  which  the  four-wheeled  collecting 
carts  and  steam  motor-wagons  tip  their  loads  direct,  no  storage 
being  provided  other  than  the  spare  carts  which  are  brought  in 
from  the  yard  and  discharged  as  required.  Sufficient  spare  wagons 
are  provided  to  keep  the  destructor  in  full  operation  day  and  night. 
The  furnaces  are  six  in  number,  each  having  42  square  feet  of 


FIG.  521.— WESTMINSTER  DESTRUCTOR.    EXTERIOR. 

grate  area.  They  are  arranged  back  to  back,  with  a  water-tube 
boiler  at  the  end  of  the  battery.  A  very  large  feed  hole,  6  feet  by 
4  feet,  is  common  to  two  furnaces,  there  being  thus  three  holes 
in  all. 

The  carts  can  be  brought  to  either  side  of  the  feed-holes  to 
dump.  Great  difficulty  was  experienced  at  first  in  arriving  at  the 
correct  shape  for  the  feed-holes — that  is,  expanding  downwards, 
as  now  shown,  so  that  the  refuse  cannot  arch  over  in  the  furnace 
mouth.  A  worse  difficulty  was  that  of  getting  such  large  lids  as 
were  required  to  be  quite  smoketight  when  closed.  Metal  to  metal 
joints  and  grooves  filled  with  sand  were  in  turn  found  unsatisfac- 
tory, and  the  handling  of  such  heavy  lids  was  also  difficult.  Even- 
tually hinged  lids,  counterbalanced  by  weights  hung  from  volute 
quadrants,  so  as  to  be  perfectly  balanced  at  all  positions,  were 
adopted. 


THE   BURNING   OF   TOWN   REFUSE.  1089 

Each  lid  dips  into  a  water-seal  which  surrounds  the  furnace 
mouth,  the  water,  which  evaporates  slowly,  being  maintained  at 
the  proper  level  by  a  ball  cock.  This  makes  a  perfectly  gas-tight 
joint,  and  not  only  is  the  trouble  of  smoke  from  the  feed-holes 
obviated,  but  it  is  found  that  the  absolute  tightness  of  the  joint, 
preventing  even  a  small  leakage,  causes  the  furnace  gases  to  pond 
up  beneath  the  lid  and  to  remain  stagnant,  thus  forming  a  shield 
of  comparatively  cool  gas,  which  protects  the  lids  from  the  furnace 


FIG.  522.— CART  TIPPING,  WESTMINSTER. 

heat.  As  long  as  there  was  any  leakage  at  all,  the  'heated  gases 
drew  that  way,  and  kept  the  furnace  mouths  and  lids  red  hot, 
which  caused  them  to  crack  and  give  trouble. 

A  hopper,  constructed  of  wrought-iron  plates  and  set  on  hinges 
in  a  position  at  right  angles  to  that  of  the  lid,  is  lowered  over  the 
opening,  so  as  to  prevent  refuse  getting  into  the  water-seal.  This 
hopper  is  balanced  in  a  similar  manner  to  that  described  for  the 
lids,  and  both  hopper  and  lids  are  easily  worked  by  hand  by  means 
of  large  chain  wheels.  The  labor  of  charging  is  thus  saved,  the 
muck  is  never  handled  at  all,  but  shot  straight  into  the  furnaces. 
This  is  an  advantage  from  a  sanitary  point  of  view,  but  it  is  not 
universally  appreciated,  as  it  puts  an  effective  stop  to  trade  in 
rags,  bones,  and  dirty  glass  bottles,  which  can  no  longer  be  picked 
out  by  the  stokers  and  sold. 


1090  THE    BURNING    OF    TOWN    REFUSE. 

Before  leaving  the  subject  of  the  Westminster  destructor,  which 
is  the  first  of  its  kind,  the  author  wishes  to  acknowledge  his  great 
indebtedness  to  the  Engineers  of  the  City,  Mr.  Bradley  and  Mr. 
Yentris,  and  to  Dr.  Priestly,  the  Medical  Officer  of  the  Health  of 
Lambeth  (whose  duty  it  was  to  inspect  the  working  of  the  plant) 
for  their  invaluable  aid  in  overcoming  the  initial  difficulties  of  the 
undertaking. 

The  author  has  already  remarked  that  he  would  like  to  see  the 
duty  of  destructors  reckoned  in  cubic  yards  rather  than  tons,  as 
giving  a  fairer  basis  of  comparison.  It  is  not,  however,  in  the  least 
likely  to  come  into  vogue,  since  the  wagon-weighing  machine  is 
such  a  simple  and  convenient  method  of  taking  the  quantities. 

26.  Labor  in  Working. — The  author  would,  however,  suggest  a 
further  reform  in  comparative  figures  to  the  effect  that  the  labor 
bill  in  working  the  furnaces  should  be  reckoned,  not  in  pence  or 
shillings  per  ton  (it  varies  even  in  England  from  sevenpence  half- 
penny at  Moss  Side  and  elsewhere  to  two  shillings  and  threepence 
at  several  London  destructors,  for  furnacemen  only),  but  in  tons 
dealt  with  per  man  per  hour.     This  would  eliminate  the  discre- 
pancies due  to  the  stokers'  wages  and  hours  of  labor  varying  so 
much  in  different  districts.     A  destructor  in  which  a  stoker  can 
deal  with  a  ton  per  hour  during  an  eight-hour  shift  may  be  con- 
sidered satisfactory,  and  this  is  being  attained  at  Westminster. 
There  can  be  no  doubt  that  a  very  large  saving  is  effected  in 
charging  direct  from  the  carts  in  the  case  of  a  destructor  dealing 
with  72  tons  of  bulky  refuse,  such  as  that  of  the  Strand  district, 
every  twenty-four  hours. 

27.  Mechanical  Stokers. — Many  attempts  have  been  made  to 
effect  tne   operations  of  stoking  and  clinkering  by  mechanical 
grates,  but  hitherto  without  much  success.     Mechanical  grates  of 
many  kinds  have  been  tried,  and  large  sums  sunk  in  such  experi- 
ments.    The  author  has  had  some  expensive  experience  in  this 
direction,  and  the  opinion  that  he  has  formed  is  that  any  attempt 
to  make  the  burning  process  continuous  instead  of  intermittent 
will  fail,  unless  some  entirely  fresh  method  be  found.    The  quality 
of  the  refuse  as  fuel  is  too  poor  to  enable  the  fire  to  creep  back 
through  a  comparatively  thin  layer  of  it  as  fast  as  the  material 
must  be  moved  forward  to  give  anything  like  a  reasonable  output ; 
vand  after  the  mechanism  has  been  set  so  as  to  give  only  about 
three  of  four  tons  per  cell  per  twenty-four  hours,  it  has  been  found 
that  the  speed  was  too  great  for  the  fire,  which  was  very  soon 


THE   BURNING   OF   TOWN   REFUSE.  1091 

all  ejected  from  the  furnace.  The  fuel  also  varies  so  much  that 
one  part  of  the  fire  will  have  become  black  clinker  while  other 
parts  are  insufficiently  burned.  Trimming  and  clinkering  by  hand 
and  the  intermittent  system  of  firing  in  one-and-a-half  or  two- 
hour  heats  at  present  hold  the  field. 

28.  Clinkering. — The  operation  of  clinkering  is  one  requiring 
both  strength  and  skill.     The  mass  of  clinker  is  often  5  inches 
thick  over  the  whole  grate  surface,  and  in  breaking  it  up  and  with- 
drawing it  from  the  furnace  the  stoker  must  be  careful  to  turn 
it  over  so  as  to  throw  off  any  live  fire  on  the  top,  which  he  after- 
wards spreads  evenly  over  the  grate  for  the  purpose  of  lighting 
the  new  charge  of  refuse.     The  blast,  which  is  shut  off  during 
clinkering,   should  be  put  on  again  for  a  few  minutes  before 
charging,  so  as  to  prepare  a  bed  of  hot  fire  for  the  reception  of  the 
charge. 

Another  method  adopted  with  some  well-known  types  of  furnace 
is  to  feed  them  continuously  from  the  front  by  hand  and  to  clinker 
also  continuously  from  each  portion  of  the  grate  surface  in  turn. 
In  furnaces  both  fed  and  clinkered  at  the  front,  no  drying  hearth 
is  provided,  and  there  is  therefore  no  preliminary  drying  of  the 
refuse.  This  system  is  adopted  by  the  author  for  small  portable 
destructors  and  furnaces  for  hospitals,  but  not  for  larger  installa- 
tions, on  account  of  the  higher  cost  of  labor.  Some  engineers  use 
continuous  grates  without  any  division  into  cells  above  the  grates, 
the  ash-pits  only  being  divided.  The  author,  however,  strongly 
favors  the  cellular  system,  which  lends  itself  much  more  readily 
to  repairs,  as  one  cell  can  be  repaired  at  a  time  without  stopping 
the  others,  thus  rendering  a  duplication  of  plant  quite  unnecessary. 

29.  Detailed  Description  of  Furnace. — The  different  methods  of 
charging  the  furnaces  having  been  described,  it  may  now  be  con- 
venient to  deal  with  the  details  of  those  parts  of  the  furnaces 
which   are  common  to  the  three   types   at   Westminster,    West 
Hartlepool,  Brussels  and  Moss  Side  respectively.     The  refuse  is 
first  piled  up  on  the  drying  hearth  above  the  main  flue  and  is 
afterwards  raked  from  the  front  on  to  the  grate-bars  as  may  be 
required.    The  drying  hearth  and  grate-bars  slope  down  about  one 
in  six  towards  the  furnace  front ;  this  greatly  reduces  the  labor  of 
working  the  furnaces.    The  grate-bars  have  narrow  spaces — about 
three-sixteenths  of  an  inch — and  are  made  in  single  lengths  of 
6  feet,  four  bars  being  cast  together.    This  enables  the  chisel  tools 
used  in  clinkering  to  be  worked  from  below  along  the  whole  length 

70 


1092  THE  BURNING  OF   TOWN   REFUSE. 

of  the  grate-bars  without  check.  A  wide  "  deadplate  "  is  provided 
in  front,  and  the  furnace  mouth  is  closed  by  a  door  extending  the 
full  width  of  the  furnace  and  lined  with  fire-brick  blocks.  The 
furnace  door  slides  upwards  to  open,  the  working  faces  being 
planed,  and  the  door  suspended  from  a  balanced  lever.  In  closing 
it  falls  into  wedge-shaped  catches  which  force  it  tight  against  its 
frame.  Such  doors  are  found  much  more  suitable  than  hinged 
doors,  which  were  commonly  used  in  early  destructors,  as  the  latter 
exposed  their  red-hot  inner  surfaces  to  the  stoker  on  being  opened. 
In  each  main  furnace  door  is  fitted  a  small  rake-door,  just  large 
enough  to  admit  the  stoker's  rake  to  enable  him  to  trim  the  fire 
and  pull  down  the  muck  without  exposing  himself  to  the  heat  of 
the  furnace.  The  main  door  need  only  be  opened  for  the  opera- 
tion of  clinkering.  The  ash-pits  are  closed  by  suitable  air-tight 
doors,  and  are  sloped  every  way  towards  the  door,  to  facilitate  the 
removal  of  ashes. 

30.  Fireclays. — The  whole  of  the  interior  of  the  furnace  is 
constructed  of  specially  made  fireclay  blocks  of  the  best  quality, 
dovetailed  together,  and  all  of  the  arched  construction.    Flat  fire- 
clay lumps  over  openings  and  flues  are  found  to  crack.     Owing  to 
the  great  heats  attained  and  the  frequent  changes  of  temperature, 
it  is  necessary  to  select  the  fireclay  with  care,  to  avoid  troubles 
from  expansion  and  contraction.     Bricks  too  rich  in  silica  expand 
and  contract  far  too  much,  and  clays  which  answer  well  for  metal- 
lurgical purposes  are  often  found  too  brittle  for  destructor  work. 
The  fireclays  which  are  found  suitable  for  use  in  destructor  fur- 
naces neither  contract  nor  expand  under  heat,  and  are  able  to 
withstand  frequent  changes  of  temperature,  the  maximum  being 
about  2,300  degrees  Fahr.    They  should  consist  of  from  60  to  70 
per  cent,  silica  and  30  to  40  per  cent,  alumina.    A  slight  admixture 
of  iron  is  harmless,  but  lime,  potash  and  soda,  which  are  usually 
found  in  such  clays,  should  only  be  present  in  very  small  quantities, 
as  they  tend  to  act  as  a  flux.     The  beds  of  fireclay  at  Leeds, 
Sheffield,   Glenboig,  near  Glasgow,  and  Stourbridge   are  all  of 
suitable   quality.      The   bricks   and   blocks   must  be  very  truly 
formed,  in  order  that  the  thinnest  possible  joints  may  be  made. 
It  is  also  important  that  the  fire-bricks  should  be  a  little  thicker 
than  the  common  bricks  with  which  they  have  to  bond,  because 
naturally  the  joints  in  the  common  brickwork  will  be  thicker  than 
would  be  desirable  in  the  fire-brick  work. 

31.  Fans  or  Steam-Blast. — The  draught  is  forced  by  means  of 


THE   BURNING   OP   TOWN   REFUSE.  1093 

fans  or  steam-jets.  The  question  as  to  which  gives  best  results, 
dry  air  or  steam-jet  blast,  is  frequently  debated.  A  blast  of  about 
.one  inch  of  water  column  is  found  to  answer  best  with  average 
refuse.  The  use  of  higher  pressures  causes  the  fire  to  burn  into 
holes  too  frequently,  and  thus  causes  too  great  an  excess  of  air  to 
pass,  and  consequently  lowers  the  temperature. 

This  pressure  can  be  obtained  easily  and  economically  either  by 
steam-jet  blast  or  by  a  centrifugal  fan.  For  working  at  a  rate  of 
10  tons  per  twenty-four  hours,  on  a  grate  area  of  30  square  feet, 
or  at  a  rate,  say,  30  pounds  of  refuse  per  square  foot  of  grate  per 
hour,  a  volume  of  about  700  cubic  feet  of  air  per  minute  at  at- 
mospheric pressure  and  temperature  for  each  cell  is  required,  or, 
say,  23  cubic  feet  of  air  per  minute  for  every  square  foot  or  grate 
area  in  use.  To  deliver  this  quantity  of  air  at  the  requisite 
pressure  requires,  with  an  efficient  steam-blast  apparatus,  about 
100  pounds  of  steam  per  hour  for  each  cell  of  30  square  feet  grate 
area,  whereas  with  a  good  centrifugal  fan  only  one-fifth  of  this 
amount,  or,  say,  20  pounds  of  steam  per  hour,  is  needed.  To 
compensate  for  the  larger  consumption  of  the  steam- jets,  it  may 
be  stated  that  they  give  a  higher  temperature  and  evaporation 
than  the  dry-air  blast,  provided  that  the  refuse  is  rich  enough  in 
carbon  to  give  the  necessary  temperature  for  the  dissociation  of 
the  steam,  which  forms  water-gas  in  the  furnace,  and  which  greatly 
improves  the  combustion.  This  action  has  been  explained  *  by 
Lord  Kelvin  and  Dr.  Archibald  Barr  in  the  following  words :  "  A 
more  important  function  is,  however,  fulfilled  by  the  steam.  In 
coming  into  contact  with  the  incandescent  fuel  it  is  decomposed, 
the  hydrogen  being  freed,  while  the  oxygen  combines  with  the 
carbon  in  the  fuel  to  form  carbon  monoxide.  This  decomposition 
of  the  water  is  effected  by  heat  abstracted  from  the  lower  part  of 
the  fire,  where  it  can  be  of  comparatively  small  value  for  the  cre- 
mation of  the  distillate.  The  '  water-gas '  (hydrogen  and  carbon 
monoxide)  passes  upwards  to  be  burned  by  the  excess  air  which  it 
meets  with  over  the  fire,  thus  serving  to  increase  the  temperature, 
which  would  otherwise  exist  at  the  meeting  of  the  products  of  com- 
bustion with  the  gases  distilled  from  the  raw  material." 

The  importance  of  the  action  of  the  steam-jet  was  strikingly 
exemplified  in  an  instance  which  came  under  the  observation  of  the 
author  at  Bury,  Lancashire,  where  in  a  new  destructor  it  was  not 

*  Report  on  the  "  Horsfall  Destructors,"  1898. 


1094  THE   BURNING   OF   TOWN   REFUSE. 

found  possible  to  reach  the  guaranteed  temperatures  in  the  flues 
by  means  of  dry-air  blast.  The  substitution  of  steam-blast  for  the 
fans  immediately  gave  and  maintained  the  required  temperature. 
It  is  fully  demonstrated  that,  provided  always  the  refuse  is  suffi- 
ciently rich  in  carbon,  a  steam-blast,  although  it  uses  more  steam 
for  the  draught,  yet  so  increases  the  amount  of  the  total  steam 
raised  as  to  give  a  better  steaming  result  on  the  whole  than  the 
fans.  With  the  refuse  of  Hamburg  and  Berlin,  however,  it  is 
doubtful  whether  the  same  can  be  said,  because  the  use  of  closed 
stoves  in  those  cities  renders  the  refuse  very  poor  as  regards  com- 
bustible cinders.  One  hundred  pounds  of  steam  used  in  the  blast 
for  each  cell  of  30  square  feet  grate  area  per  hour  may  be  con- 
sidered a  very  good  result  for  steam-blast,  and  it  can  only  be 
secured  by  using  efficient  arrangements. 

A  steam-jet  has  been  devised  by  Mr.  C.  W.  James,  in  conjunc- 
tion with  the  author,  for  this  purpose,  in  which  the  nozzle  is  flat 
instead  of  round,  thus  yielding  a  ribbon  of  steam  instead  of  a  plug 
of  steam.  It  is  probable  that  the  air  is  carried  through  the  blast- 
tube  mainly  by  means  of  surface  friction  between  the  jet  of  steam 
and  the  surrounding  column  of  air,  and  it  is  therefore  advantage- 
ous to  have  the  greatest  possible  surface  on  the  steam-jet  per 
pound  of  steam  passing.  This  is,  of  course,  obtained  by  making 
the  jet  flat  and  thin.  A  thickness  of  one-fortieth  of  an  inch  is 
found  best.  It  is  also  important  that  the  steam  should  be  super- 
heated, so  as  to  prevent  condensation  and  obstruction  in  the  nozzle 
itself.  A  pressure  of  30  to  40  pounds  to  the  square  inch  for  the 
steam-blast  gives  the  most  economical  results.  Keducing-valves 
are  used,  giving  this  pressure  whatever  may  be  the  working 
pressure  of  the  boiler. 

A  further  great  advantage  to  be  set  down  to'  the  credit  of  the 
steam-blast,  as  compared  with  fan  draught,  is  the  fact  that  it  pro- 
tects and  lengthens  the  life  of  the  ironwork  exposed  to  heat  in  the 
furnaces,  such  as,  for  instance,  grate  bars  and  the  cast-iron  side- 
boxes  which  are  used  for  heating  the  blast.  After  leaving  the 
nozzle  the  steam  in  the  blast  is  condensed,  and  it  reaches  these 
iron  parts  in  the  form,  of  particles  of  water.  On  striking  the  hot 
iron  it  is  immediately  re-evaporated  into  steam,  carrying  with  it  a 
considerable  amount  of  heat,  and  thus  keeping  down  the  tempera- 
ture of  the  ironwork.  The  author  has  seen  grate  bars  taken  out 
of  a  furnace  after  six  years'  constant  use  very  little  the  worse  for 
wear,  whereas  with  dry  air-blast  and  high  temperatures  the  grate 


THE   BURNING   OF   TOWN   REFUSE.  1095 

bars  would  require  to  be   renewed  after  six  months  to  twelve 
months  at  the  latest. 

32.  Cast-iron  Furnace  Sides. — The  steam-jet  trumpets  used  in 
the  West  Hartlepool  installation  are  combined  with  the  cast-iron 
side-boxes  which  form  the  sides  of  the  furnaces  above  and  below 
the  grate-bars.      These  side-boxes  serve  the   double  purpose   of 
heating  the  blast  to  a  temperature  of  400  degrees  Fahr.  in  the  ash- 
pit and  of  protecting  the  brick-work  at  the  sides  of  the  furnace 
from  the  undermining  action  of  the  hot  clinker.     In  furnaces 
with  brick-work  sides,  at  the  first  level  it  is  found  that  the  clinker 
fuses  to  the  brick-work,  and  every  time  it  is  removed  brings  away 
particles  of  the  wall,  thus  gradually  undermining  it,  and  allowing 
the  crown  of  the  furnace  to  fall  before  it  is  anything  like  worn 
out.     The  side-boxes,  which  are  kept  cool  by  the  passage  of  the 
cold  air  and  by  the  cooling  action  of  the  steam  above  described, 
prevent  this  action.     The  air  is  drawn  into  the  boxes  from  hoods, 
something  like  the  hood  over  a  blacksmith's  fire,  placed  over  the 
clinker-door  in  such  a  position  as  to  draw  off  any  smoke  and  dust 
rising  during  the   operation  of  clinkering.      This  improves   the 
ventilation  of  the  stoke-hole. 

33.  Firing  Tools. — The  firing  tools  consist  of  prongs  or  pushers 
for  charging  the  furnaces,  light  and  heavy  rakes,  for  pulling  down 
and  clinkering  respectively,  and  chisel  bars.     They  are  all  neces- 
sarily long,  and  any  means  of  making  them  lighter,  without  re- 
ducing their  strength,  is  worth  adopting.    It  is  found  a  good  plan 
to  use  a  weldless  steel  tube  for  rake  handles,  and  to  make  the  chisel 
bars  of  solid  masons'  tool  steel  in  order  to  get  the  greatest  possible 
strength. 

34.  Boilers. — In  the  early  destructor  plants  multitubular  boilers 
of  plain  cylindrical  shape,  with  fire-tubes  about  3  inches  or  4 
inches   in   diameter,   were   frequently  used.      One   of  the   most 
serious  drawbacks  to  these  was  the  fact  that  the  dust  carried  in 
the  gases  soon  choked  up  the  tubes,  which  had  to  be  brushed  out 
three  or  four  times  in  the  course  of  a  day,  and  an  even  worse 
defect  was  the  stiffness  of  the  boiler,  which  did  not  easily  yield  to 
expansion  and  contraction.     A  destructor  boiler,  placed  at  the  end 
of  the  main  flue,  is,  of  course,  really  a  gas-fired  boiler,  and  it  is 
subject  to  having  the  gases  switched  on  or  off  instantaneously. 

It  was  found  that  with  these  multitubular  boilers  the  tubes  very 
soon  began  to  leak  at  the  tube  plate;  moreover,  boilers  of  such  a 
large  diameter  as  were  generally  used  were  not  very  suitable  for 


1096  THE  BURNING  OF   TOWN   REFUSE. 

high  pressures,  unless  they  were  constructed  in  a  very  expensive 
manner.  For  these  reasons  such  boilers  are  now  only  used  for 
very  small  installations,  or  where  steam-raising  is  a  matter  of  little 
importance. 

It  is  essential  that  a  boiler  which  permits  its  tubes  to  expand 
and  contract  very  freely  should  be  used. 

The  two  types  of  boiler  most  favored  at  the  present  time  in 
connection  with  destructors  are  the  Lancashire  type  and  the  water- 
tube  type.  The  former  has  the  advantage  of  large  capacity  for 
storage  of  hot  water  and  steam,  and  it  is  also  less  susceptible  to 
troubles  arising  from  hard  water,  but  it  is  found,  when  using 
destructor  gases,  that  the  flue  area  is  insufficient  unless  the  boiler 
be  made  larger  than  would  be  usually  adopted  for  the  same  rate  of 
evaporation  when  fired  in  the  ordinary  way  with  coal.  A  deposit 
of  dust  in  the  two  flues  of  the  boiler  is  not  a  very  serious  draw- 
back, as  the  boiler  is  easily  cleaned,  and  the  lower  half  of  the  flue 
is,  of  course,  less  valuable  as  heating  surface  than  the  upper  half. 
A  well-constructed  Lancashire  boiler  is  also  able  to  withstand  the 
effects  of  expansion  and  contraction,  due  to  the  hot  gases  being 
suddenly  switched  on  or  off  by  means  of  the  by-pass  damper. 

In  cases  where  the  destructor  has  to  work  continuously,  while 
the  power  is  only  required  for,  say,  three  or  four  hours  a  day  (so 
often  in  the  case  in  electricity  stations)  the  large  capacity  of  the 
Lancashire  boiler  for  storage  of  steam  power  is  very  valuable. 

The  water-tube  boiler,  however,  seems  destined  to  have  the 
preference  in  most  new  destructor  installations.  In  the  first  place, 
it  is  specially  adapted  for  high  pressures. 

Steam  is  raised  very  quickly,  which  is  a  great  advantage  in 
starting  the  destructor  at  the  beginning  of  each  week,  because  the 
forced  draught  cannot  be  put  into  operation  until  steam  has  been 
raised.  The  water-tube  boiler  is  well  adapted  for  resisting  the 
sudden  changes  of  temperature  to  which  it  is  subjected  in  a 
destructor,  and  it  provides  ample  area  for  the  passage  of  the  gases 
in  proportion  to  its  heating  surface.  It  has  another  great  advantage 
in  the  fact  that  dust  can  only  lodge  on  the  tops  of  the  tubes  (when 
in  proportion  to  its  heating  surface.  It  has  another  great  advan- 
tage in  the  fact  that  dust  can  only  .lodge  on  the  tops  of  the  tubes 
(when  the  tubes  are  horizontal  or  sloping),  leaving  the  lower  sur- 
faces, which  are,  of  course,  the  most  effective,  always  clean.  The 
dust  can  be  readily  removed  by  means  of  steam-jets  applied 
through  suitable  cleaning  holes,  provided  in  the  brick-work  sides 
of  the  boiler  seating. 


THE  BURNING  OP  TOWN  REFUSE.  1097 

When  water-tube  boilers  with  vertical,  or  nearly  vertical,  tubes 
are  used,  dust  cannot  lodge  at  all,  and  as  there  is  no  soot  in 
destructor  gases,  an  externally  clean  heating  surface  is  always 
presented.  It  may  also  be  remarked  that  boilers  of  the  water-tube 
type  can  be  arranged  closer  to  the  end  of  the  battery  of  destructor 
cells,  and  the  damper  arrangements  can  be  made  more  convenient, 
than  when  boilers  of  the  Lancashire  type  are  used. 

35.  Fuel  Economizers. — Seeing  that   the   destructor   depends 
much  more  upon  forced  draught  than  upon  the  pull  of  the  chim- 
ney, it  is  economical  to  carry  the  reduction  of  the  temperature 
of  the  gases  at  the  chimney  base  to  a  low  point,  say  between  400 
degrees  and  500  degrees  Fahr.,  and  fuel  economizers  are  fre- 
quently placed  in  the  flues  behind  the  boilers.     These  should  'be, 
like  the  boilers,  arranged  so  that  the  gases  can  be  by-passed  at 
short  notice. 

36.  Utilization  of  Heat. — The  heat  of  the  gases  from  destruc- 
tors, although,  as  stated  above,  of  considerable  value,  is  unfor- 
tunately often  lost  through  lack  of  convenient  application  near  to 
the  site  of  the  destructor.     It  is  a  curious  fact  that,  although 
electric-lighting  stations  only  demand  a  considerable  quantity  of 
power  during  three  or  four  hours  per  diem,  the  combination  of 
destructors   with   electricity  stations   is  the   commonest  method 
of  utilizing  the  heat.    There  are,  however,  other  kinds  of  munici- 
pal work  that  can  absorb  a  fair  proportion  of  the  power  available. 
Stone-breaking,    crushing   and   screening   the   clinker   from   the 
destructors,  or  grinding  it  into  mortar,  driving  repairing  shops, 
sawing,  chaff-cutting,  sewage  and  water-pumping,  heating  baths 
and  wash-houses,  and  even  schools  and  dwellings,  have  been  car- 
ried out  in  different  places  by  means  of  the  steam  from  destructors. 

At  Moss  Side  (Manchester)  a  snow  melting  pit  has  been  con- 
structed by  the  Municipal  Engineer — Mr.  Longley — in  which  a 
series  of  pipes  bringing  steam  from  the  destructor  boilers  is  placed. 
These  are  perforated  so  as  to  throw  jets  of  hot  steam  upon  the 
snow  as  it  is  tipped  into  the  melting  pit. 

At  Folkestone,  the  Borough  Engineer — Mr.  Nichols — has  con- 
structed heating  pans  on  the  flues  beyond  the  economizer  for  the 
purpose  of  warming  the  materials  for  use  in  forming  streets  of  tar 
Macadam. 

37.  Dust-catcher. — A  dust-catcher  has  been  placed  between  the 
boiler  and  the  chimney  in  the  installations  at  Brussels,  West 
Hartlepool,  Moss  Side,  and  in  many  other  recent  destructors.   The 


1098 


THE  BURNING   OF   TOWN   REFUSE. 


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15  Feet 


Am. Bank  Kote  Co.,ff.T. 


FIG.  523. — DUST- CATCHER. 

5-Cell  Destructor  for  Blackpool. 


THE  BURNING  OF  TOWN   REFUSE.  .         1099 

latest  form  of  this  apparatus  has  been  devised  by  Messrs.  Newton 
and  Diggle,  of  Accrington,  in  conjunction  with  the  author,  and  it 
consists  of  a  swirling  chamber,  into  which  the  gases  are  led  from 
the  main  flue  in  such  a  manner  as  to  give  them  a  circular  or 
revolving  motion  within  the  chamber,  Fig.  523.  In  carrying 
this  out  they  are  made  to  pass  round  an  annulus  formed  by  the 
outer  circular  wall  and  the  inner  well,  built  up  to  within  a  short 
distance  of  the  domed  or  arched  roof.  The  whole  of  the  interior 
is  lined  with  fire-brick  to  enable  the  apparatus  to  deal  with  red-hot 
gases  when  the  boilers  are  not  in  use.  The  rapid  revolution  of  the 
gases  within  this  chamber  throws  all  the  suspended  dust — even  the 
smallest  particles — against  the  outside  wall  of  the  chamber  by 
centrifugal  force. 

At  intervals,  vertical  slits  are  provided,  leading  into  pockets 
outside  the  chamber. 

The  dust,  travelling  along  the  outer  wall,  finds  its  way  into  these 
slits  and  thence  into  the  pockets,  where  the  gases  are  stagnant,  and 
where  the  dust  falls.  The  vertical  slits  leading  into  these  pockets 
can  be  closed  by  suitable  doors  hung  freely  on  ball-bearings  and  so 
arranged  that  whenever  the  outer  cleaning  door  of  the  pocket  is 
opened  for  the  purpose  of  withdrawing  the  dust  the  door  covering 
the  inner  opening  is  closed  by  suction. 

With  this  apparatus  it  is  possible  to  extract  the  dust  from  any 
or  all  of  the  pockets,  without  interfering  with  the  draught  of  the 
destructor.  This  is  important  when  destructors  are  combined 
with  electricity  stations,  as  at  Accrington,  because  it  is  never  prac- 
ticable to  allow  the  flues  to  get  cool  enough  to  clean  out  by  hand. 
Not  only  the  dust-catcher  itself,  but  the  whole  of  the  flues  through- 
out the  destructor  and  boiler  can  be  cleaned  by  simply  opening 
the  end  doors,  and  allowing  the  wind  to  rush  through,  whipping  up 
the  whole  of  the  dust  deposited  in  the  flues,  and  carrying  it  for- 
ward into  the  dust-catcher,  where  the  centrifugal  action  discharges 
it  into  the  pockets  above  described.  It  will  be  observed  that  the 
stronger  the  draught,  the  more  complete  is  the  separation  of  the 
dust. 

38.  Dampers. — Dampers  of  many  kinds,  including  cast-iron 
(with  and  without  ribs),  wrought-iron  and  steel  plates  of  different 
thicknesses  have  been  tried.  Cast-iron  gas-valves,  with  cold-water 
circulation,  have  also  been  extensively  used.  The  latter  were  suc- 
cessful until — as  always  happened  sooner  or  later — the  water  sup- 
"ply  was  interrupted,  by  accident  or  design,  when  they  would  imme- 


1100  THE  BURNING  OF   TOWN   REFUSE. 

diately  fail.  Experience  seems  to  point  to  a  damper  formed  of 
fire-brick  blocks  in  a  suitably  designed  cast-iron  frame  as  the  most 
reliable  for  general  purposes.  The  damper  should  be  set  in 
grooves  deep  enough  to  protect  the  frame  from  the  action  of  hot 
gases.  It  should  also  be  provided  with  suitable  means  for  making 
the  slit  at  the  top  practically  air-tight,  when  the  damper  is  either 
closed  or  open. 

The  author  has  recently  adopted  double  by-pass  dampers  for  the 
by-pass  to  the  boilers.  These  are  found  to  be  practically  gas-tight, 
as  the  damper  nearest  to  the  chimney  so  reduces  the  tension  of  the 
draught  that  the  leakage  past  the  second  damper,  with  which  the 
gases  come  earliest  in  contact,  is  negligible. 

39.  Chimneys. — A  dissertation  on  destructor  chimney  shafts 
would  be  out  of  place  in  a  paper  which  has  already  run  to  con- 
siderable length,  but  it  may  be  remarked  in  passing  that,  unless 
in  very  special  circumstances,  a  destructor  chimney  need  not  ex- 
ceed from  100  feet  to  120  feet  in  height.     Even  at  the  West- 
minster destructor,  which  is,  as  before  stated,  in  the  heart  of 
London,  the  height  of  the  chimney  above  ground  line  is  only  90 
feet,  and  the  destructor  is  worked  without  complaint.     In  fact,  it 
may  be  said  that  it  is  difficult  to  tell  by  observation  of  the  chimney 
whether  the  plant  is  at  work  or  not. 

Destructor  chimneys  should  be  constructed  to  withstand  the 
full  heat  of  the  gases,  which  are  sometimes  directed  into  them 
without  passing  through  either  boilers  or  economizers.  For  this 
reason  they  should  invariably  be  lined  to  the  top  with  fire-brick, 
and  it  is  good  practice  also  to  provide  an  air  space,  properly  ven- 
tilated, between  the  fire-brick  lining  and  the  outer  shell. 

40.  Clinker-handling. — To  come  now  to  some  of  the  machinery 
accessory  to  destructors,  it  may  be  mentioned  that  one  of  the  most 
important  points  is  the  handling  of  the  hot  clinker  as  it  is  with- 
drawn from  the  furnace.    At  Moss  Side,  and  also  at  Westminster, 
overhead  railways,  on  the  system  devised  by  Mr.  Cox,  City  En- 
gineer of  Bradford,  and  the  late  Mr.  McTaggart,  are  used.    These 
railways  consist  of  a  single  H  beam  suitably  suspended,  on  which  a 
small  trolley,  with  ball  or  roller  bearings,  runs  freely,  Fig.  519  and 
Fig.  524.    From  the  trolley  hangs  a  large  tipping  truck  of  suitable 
capacity  for  taking  the  whole  of  the  clinker  from  the  cleaning  of  a 
single  cell.    This  represents  two,  and  even  sometimes  three,  very 
large  barrow-loads,  which  would  be  heavy  labor  to  wheel.      The 
clinker  truck  is  suspended  immediately  under  the  lip  of  the  front 


THE   BURNING  OF   TOWN   REFUSE. 


1101 


dead-plate,  so  that  the  clinker  can  be  withdrawn  directly  into  it. 
It  is  then  pulled  away  by  the  stoker  along  the  runway  over  the 
clinker  cooling  bed,  and  tipped  on  its  own  trunnions  so  as  to  dis- 
charge the  clinker  on  the  ground,  where  it  is  allowed  to  cool. 
These  railways  are  capable  of  considerable  modification  to  suit 
different  sites.  For  instance,  at  Westminster,  where  the  plant 
is  sunk  below  ground  level,  a  section  of  the  rail  is  lifted  on  a 


T 


Ins.  12 


'JTatson  Geo. 

FIG.  524. — OVERHEAD  CLINKER  RAILWAY  AND  BUCKET. 


8  Feet 

Am. Bank  Note  Co.,N.  Y. 

Moss  SIDE. 


suitable  hoist,  and  it  is  also  provided  with  a  revolving  arrangement, 
so  as  to  command  several  sets  of  rails  at  the  top.  Turntables  are 
also  easily  contrived  and  worked. 

41.  Clinker  Crushers  and  Screens. — Suitable  clinker  crushers 
and  screens  for  preparing  the  material  for  concrete  work,  such  as 
fire-proof  floors,  road  foundations,  and  the  like,  have  been  de- 
signed also  by  Messrs.  Cox  and  McTaggart,  and  are  extensively  in 
use.  The  crushers  consist  of  a  pair  of  fluted  rollers  mounted  on 
wooden  keys  so  as  to  give  the  necessary  elasticity  to  avoid  breakage 
when  pieces  of -iron  are  encountered.  The  yield  of  the  keys  is 
sufficient  to  stop  the  machine  gradually,  and  not  instantaneously, 
and  has  the  effect  of  throwing  off  the  belt  of  the  machine,  and 


1102  THE   BURNING  OF   TOWN   REFUSE. 

avoiding  the  sudden  jar  which  would  cause  breakage.  The  screens 
deliver  the  material  in  sizes  required  for  the  various  works  to  be 
undertaken. 

42.  Paving  Flags. — Attention  has  recently  been  given  also  to 
the  production  of  concrete  flags  for  footways,  and  to  mixing  and 
pressing  machinery  for  making  building-bricks. 

43.  Clinker  Bricks. — Dr.  Schultess,  of  Zurich,  has  worked  out 
a  very  complete  system  for  the  production  of  bricks  from  clinker 
and  lime.     One  of  the  features  of  his  system  is  the  lime-slaking 
machine,  which  produces  a  perfect  lime  in  a  dry  powder,  free  from 
nodules,  and  slaked  with  exactly  the  proper  amount  of  water.    He 
also  provides  mixing  machinery  arranged  so  as  to  automatically 
mix  the  correct  quantities  of  ground  clinker,  lime  and  water,  and 
one  of  the  advantages  to  which  he  draws  special  attention  is  the 
fact  that  no  water  need  be  expressed  from  the  flag  under  corn- 
pressure,  the  amount  of  moisture  supplied  being  what  is  required 
for  the  proper  setting  and  no  more.     This  enables  a  brick  or  flag 
with  very  clean  arrises  to  be  produced.    A  further  feature  of  Dr. 
Schultess's  system  is  the  maturing  of  the  final  product  in  forty- 
eight  hours  by  means  of  steam  at  atmospheric  pressure. 

Bricks  and  flags  so  produced  have  a  strength  considerably 
exceeding  that  of  good  burned  clay  bricks,  and  the  bricks  are 
suitable  for  foundation  work,  embankment  walls,  and  for  inner 
walls  of  houses.  Their  dark  color  is  a  drawback  to  their  adoption 
for  outer  walls.  In  the  ordinary  way  Portland  cement  is  used 
for  such  productions,  but  Dr.  Schultess  claims  to  get  a  better 
result  with  lime,  and,  of  course,  at  a  lower  cost. 

44.  Clinker  Mortar. — Mortar  made  from  clinker  and  lime  is 
found  to  be  almost  equal  to  hydraulic  mortar,  and  it  is  capable  of 
withstanding  considerable  heat.     In  fact,  in  destructors  at  Old- 
ham,  Bradford  and  elsewhere  it  is  frequently  used  for  pointing  up 
the  interior  of  the  furnaces,  and  is  found  to  stand  as  well  as  fire- 
clay. 

45.  Destructors  for  Hospitals,  etc. — Destructors  of  small  size, 
suitable  for  villages  and  public  institutions,  such  as  hospitals  or 
large  hotels,  have  been  alluded  to  above.     No  special  remark  is 
called  for  respecting  the  design  of  such  furnaces,  except  that  they 
should  be  of  the  simplest  character.    As  a  rule  they  are  both  fired 
and  clinkered  at  the  front  through  the  clinkering-door.  In  other 
respects,  such  as  in  the  details  of  grate  bars,  cast-iron  side-boxes, 
forced-draught  apparatus,  front-flue  openings,  and  so  forth,  the 


THE   BURNING   OF   TOWN   REFUSE. 


1103 


design  of  the  larger  types  of  furnaces  is  followed.  In  come  cases, 
however,  where  it  is  impossible  to  get  steam  for  steam-blast  or 
electric  current  for  fan  draught,  such  furnaces  have  to  be  worked 
by  means  of  strong  natural  draught. 

46.  Portable  Destructors. — "  Portable "  destructors  are  also 
made,  consisting  of  a  furnace  following  the  above  general  lines, 
attached  to  a  plain  cylindrical  "  multitubular  "  boiler  with  a  dust- 
catcher  in  the  smoke-box,  steam-jet  forced  draught  and  a  short 
chimney;  the  whole  being  mounted  on  wheels  for  transport.  The 


FIG.  525. — PORTABLE  DESTRUCTOR. 

weight  of  the  destructor  illustrated,  Fig.  525,  is  between  6  and  7 
tons,  and  the  capacity  about  4  tons  of  muck  in  the  24  hours. 
These  small  "  portable  "  destructors  are  good  steam-raisers,  and 
when  used  in  connection  with  hospitals  the  power  may  be  con- 
veniently utilized  in  connection  with  electric  lighting  plant, 
Eontgen  ray  apparatus,  disinfecting  chambers,  and  the  like.  They 
are  also  intended  to  be  worked  when  stationary. 

A  still  smaller  destructor  has  been  devised  by  the  author's 
brother,  Mr.  F.  L.  Watson,  for  military  purposes,  consisting  of  a 
small  furnace  combined  with  sterilizing  tanks,  in  which  infected 
clothing,  etc.,  can  be  dealt  with,  the  whole  being  mounted  on  two 
wheels  and  suitable  for  mule  or  horse  transport.  There  can  be  no 
doubt  that  a  convenient  apparatus  of  this  kind,  if  available  at  all 


1104  THE   BURNING   OF   TOWN   REFUSE. 

standing  and  advanced  camps,  would  materially  lessen  the  ravages 
of  zymotic  diseases  in  time  of  war. 

In  conclusion,  the  author  begs  to  acknowledge  his  indebtedness 
to  many  engineers,  in  not  a  few  instances  friends  of  his  own,  for 
their  labors  in  connection  with  the  disposal  of  refuse  by  fire,  and 
he  trusts  that  the  above  notes  of  his  own  experience  may  be  of 
interest  and  of  service  to  the  members  of  the  Institution. 


APPENDIX    I. 

THE  DESTRUCTOR  AT   WEST  HARTLEPOOL. 
TEST  REPORT. 

NOTE.— The  following  figures  and  the  accompanying  diagram,  Fig.  526,  give  the  mean  results 
of  the  two  days. 

Date  of  test 28th  and  29th  Jan.,  1904. 

Duration  of  test 48  hours. 

Number  and  type  of  cells 6  back-to-back. 

Total  grate  surface 180  square  feet. 

System  of  forced  draught Steam  jets. 

Nature  of  refuse Ashpit,  nightsoil,  market. 

Number  of  firemen  and  average  wage  per  day 9  at  5  shillings. 

( 1  Babcock  and  Wilcox,  2,393 

Number,  size,  and  type  of  boilers ] 

(     square  leei. 

Tons.  cwt.  qr.  Ibs. 

Total  quantity  of  refuse  burned 272,432  Ibs.  =  121     12    1    20 

"  "      per  cell  per  24  hours 22,703  Ibs.  =    10      2    2    23 

"  "  "      per  square    foot  of    grate 

per  hour 31.5. 

Tons  per  man  per  shift 6.7  tons. 

Cost  of  labor  per  ton  burned 8.9  pence. 

Total  water  evaporated 348,673  Ibs. 

"  "          per  hour 7,264  Ibs. 

"         "  "         per  square   foot   of  heating 

surface  per  hour 3.03  Ibs. 

"         "  "          per  Ib.  of  refuse  from  and  at 

212  deg.  Fahr.  or  100  deg.  C.I. 56  Ibs. 

Mean  steam  pressure 155  Ibs.  per  square  inch. 

"     feed  temperature 43  degrees  Fahrenheit. 

c  Above  2,000  deg.   Fahr.   (be- 

mam  flue  temperature 1  . 

I     yond  range  of  Pyrometer). 

"    temperature  behind  boiler 534  degrees  Fahrenheit. 

Horse-power  developed  at  20  Ibs.  steam  per  indicated 

horse-power  per  hour 363. 

Purpose  for  which  steam  is  utilized Electric  lighting. 


THE   BURNING   OF   TOWN   REFUSE. 


1105 


g  |    °Z  S     6|  g     s  .     5. 

1    fill,  II  !  i  3 

«  4  8.2  _i  ss  i*  •:- 

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1106  THE  BURNING  OF   TOWN  REFUSE. 

APPENDIX   II. 

CITY  OP   WESTMINSTER. 
TEST  REPORT. 

Date  of  test  ....................................  2d  Dec.,  1902,  to  4th  Dec.,  1902. 

Duration  of  test  ................  ,  ..........    ....  45£  hours. 

Number  and  type  of  cells  ......................  6  back-to-back  direct  cart-fed. 

Total  grate  surface  .............................  252  square  feet. 

System  of  forced  draught  .......................  Steam  jets. 

Nature  of  refuse  -----  ..........................  House,  trade,  and  market. 

AT      T-  (9  stokers  at  35  shil.  per  week. 

Number  of  firemen  and  average  wage  per  day.  .  .  4  . 

]  4  top  men  at  27s.  6d.  per  week. 

Number,  size,  and  type  of  boilers  ................  1  water-tube,  1,426  sq.  ft.  H.  S. 

Tone.  cwt.  qrs.  Ibs. 
Total  quantity  of  refuse  burned  .................  138    15      1     0  =  310,828   Ibs. 

"      per  cell  per  24  hrs.  12  5       18=    27,476  Ibs. 
"           "         "       "            "      per  square   feet  of 

grate  per  hour.  .  —  —     —  —           27.2  Ibs. 

Tons  per  man  per  shift  ..........................    8  325 

11.5    pence,  exclusive    of  en- 
Cost  of  labor  per  ton  burned  .................... 

gineman  and  foreman. 

Total  water  evaporated  .......................  ] 

"  "         per  hour  ............... 

"         "  «         per  square  foot  of  heating      Test    for    evaporation    aban- 

surface  per  hour  ......  \       doned»    boiler    blow1^    off 

perlb.  of  refuse  from  and  I        very  heavily. 

at  212°  F.  or!00°C...J 

Percentage  of  clinker  and  ash  to  refuse  burned.  .  .24.9  per  cent. 
Mean  steain  pressure  ............................  125  Ibs.  per  square  inch. 

'  '     feed  temperature  ..........................  48  degrees  Fahrenheit. 

(  Well  over  2,000  degrees  Fahr. 
"    main  flue  temperature  ...................  l         ,         ,      „  ,    A 

\     softened  mild  steel. 

"    temperature  behind  boilers  ................  500  degrees  Fahrenheit. 

(Electric     light,     steam      jets, 
Purpose  for  which  steam  is  utilized  ............ 


DISCUSSION. 

Mr.  J.  Hartley  Wicksteed.*  —  I  know  Mr.  Watson  very  well, 
and  I  may  say  that  he  has  been  extremely  successful  with  Mr. 
HorsfalPs  destructor.  Destructors  are  very  difficult  things  to 
undertake,  because  the  town  refuse  varies  so  much  in  quality  in 
the  different  towns,  and  it  requires  a  very  great  deal  of  exper- 
ience to  hit  off  a  result  that  you  can  guarantee.  The  original 
basis  which  differentiated  Mr.  HorsfalPs  destructor  from  others 
was  the  use  of  the  steam  jet.  The  action  of  the  steam  jet  is  very 

*  President  of  the  Institution  of  Mechanical  Engineers. 


THE   BURNING  OF   TOWN  REFUSE.  1107 

abstruse,  but  it  has  been  reported  upon  by  Lord  Kelvin  and  Dr. 
Barr,  and  I  will  presently  read  to  you  one  paragraph — not  that  I 
wish  to  direct  your  discussion  to  that  particular  point,  but  because 
it  was  what  started  this  company  making  destructors.  Of  course, 
experience  has  shown  that  there  are  a  hundred  considerations 
which  are  of  quite  equal  importance  to  the  original  idea  con- 
cerning the  utility  of  the  steam  jet,  but  still  you  must  have 
something  to  start  with,  and  Mr.  Watson's  company  had 
this  to  start  with  and  they  worked  at  it  and  it  lead  them  into  the 
knowledge  of  all  the  other  points.  The  thing  itself  I  have,  no 
doubt,  is  of  considerable  value.  The  author  says  in  his  paper,  "  it 
may  be  stated  that  they  (that  is,  the  steam  jets)  give  a  higher  tem- 
perature and  evaporation  than  the  dry-air  blast,  provided  that  the 
refuse  is  rich  enough  in  carbon  to  give  the  necessary  temperature 
for  the  dissociation  of  the  steam,  which  forms  water-gas  in  the 
furnace,  and  which  greatly  improves  the  combustion. 

This  action  has  been  explained  by  Lord  Kelvin  and  Dr.  Archi- 
bald Barr  in  the  following  words : 

"  A  more  important  function  is,  however,  fulfilled  by  the  steam. 
In  coming  into  contact  with  the  incandescent  fuel  it  is  decomposed, 
the  hydrogen  being  freed  while  the  oxygen  combines  with  the 
carbon  in  the  fuel  to  form  carbon  monoxide.  This  decomposition 
of  the  water  is  effected  by  heat  abstracted  from  the  lower  part  of 
the  fire,  where  it  can  be  of  comparatively  small  value  for  the 
cremation  of  the  distillate.  The  water-gas  (hydrogen  and  carbon 
monoxide)  passes  upwards  to  be  burned  by  the  excess  air  which 
it  meets  with  over  the  fire,  thus  serving  to  increase  the  temperature 
which  would  otherwise  exist  at  the  meeting  of  the  products  of  com- 
bustion with  the  gases  distilled  from  the  raw  material." 

So  that  it  seems  the  chief  function  of  the  steam  jet  is  to  shift 
the  locality  of  the  intensest  heat  of  the  fire. 

This  paper  and  Mr.  Russell's  paper  were  prepared  at  the  request 
of  the  American  Society,  and  we  from  England  have  put  before 
you  the  best  knowledge  possessed  by  any  members  of  our  Institu- 
tion, and  I  hope  you  will  take  the  matter  up  for  discussion. 

Mr.  Alfred  Saxon.* — Sanitary  engineering  up  to  the  present 
has  had  no  particular  attractions  for  me;  in  fact  I  have  rather 
looked  upon  the  science  as  a  necessary  evil,  but  seeing  that  the 
paper  as  presented  seemed  to  my  mind  to  be  representative  of  the 
engineering  of  Leeds  and  its  district,  I  thought  I  would  see 

71         *  Member  of  the  Institution  of  Mechanical  Engineers. 


1108  THE  BURNING  OF   TOWN   REFUSE. 

whether  no  good  thing  could  come  from  Manchester,  which  I  rep- 
resent, and,  as  a  matter  of  fact,  I  believe  we  have  the  best  destruc- 
tor for  the  purpose  produced  in  the  Manchester  district. 

There  are  some  points  of  agreement  on  this  question,  notably 
in  respect  to  the  quality  of  the  refuse.  I  find  that  the  people  who 
have  spoken  and  written  upon  this  question  agree  with  the  state- 
ment of  the  author  that  an  average  for  this  is  one-third  by  weight 
of  water,  one-third  combustible  matter,  and  one-third  incom- 
bustible. On  other  points,  of  course,  there  are  differences  of 
opinion.  The  claim  that  Mr.  Watson  makes,  for  the  isolated  cell 
system  at  West  Hartlepool  works,  does  not,  as  a  matter  of  fact, 
seem  to  be  sustained,  nor  does  it  produce  results  which  will  com- 
pare with  the  continuous  grate  system  which  is  adopted  by  the 
Manchester  firm.  The  claim  also  made  by  the  author  about  the 
ease  of  repairs  in  the  isolated  cells  is  doubtful,  when  one  cell  is 
adjacent  to  another,  working  at  2,000  degrees  Fahrenheit,  is  it 
not  rather  too  much  to  expect  that  much  good  work  will  be  done 
in  the  cells  which  are  supposed  to  be  isolated,  but  which  must  to  a 
certain  extent  be  heated  up  by  the  cells  which  are  in  work. 

Now,  I  should  like  to  make  a  comparison  of  the  test  which  is 
given  in  the  paper  with  one  which  was  made  by  the  National  Boiler 
Insurance  Co.  at  Woolwich  on  the  Destructor  erected  by  Messrs. 
Meldrum  Bros.,  Timperley.  At  Woolwich  on  three  grates,  75 
square  feet,  63 J  tons  of  refuse  were  burned  in  24  hours,  and  each 
pound  of  refuse  evaporated  1.9  of  water.  Whereas  at  Hartlepool, 
in  the  test  given  in  the  paper,  on  180  square  feet,  they  burned 
121  tons.  In  the  one  case,  at  Woolwich,  at  77  pounds;  whilst  in 
the  other  case  only  31  pounds  per  square  foot. 

Mr.  Edward  N.  Trump. — While  the  papers  presented  by  our 
English  friends  on  the  above  subject  are  of  great  interest  as  show- 
ing engineering  skill  in  handling  a  difficult  problem,  from  the 
point  of  view  of  the  chemical  engineer  the  very  name  "  destruc- 
tor "  suggests  a  process  which  should  only  be  a  last  resort  in  the 
utilization  of  our  wastes. 

The  remains  of  the  beefsteak  for  which  you  paid  two  dollars 
a  pound,  and  failed  to  eat  because  of  a  bad  appetite  ;  the  butter  left 
on  your  plate ;  and  trimmings  from  the  raw  materials ;  which  from 
such  a  large  percentage  of  the  food  which  is  finally  consumed,  all 
contain  valuable  ingredients  which  should  be  utilized  not  destroyed. 

The  work  in  the  United  States  has  been  more  in  the  direction 
of  the  "  reduction  "  of  "  garbage  "  or  kitchen  waste,  to  its  useful 


THE   BURNING  OF   TOWN   REFUSE.  1109 

constituents  rather  than  its  destruction.  The  fermentation  which 
so  quickly  starts  up  in  these  waste,  producing  a  crop  of  germs  very 
dangerous  to  the  health  of  the  community  may  be  stopped,  and 
the  waste  thoroughly  sterilized  by  boiling  under  high  pressure, 
and  the  valuable  greases  and  liquids  saved  and  utilized. 

First,  The  waste  must  be  gathered  as  frequently  as  possible  to 
reduce  the  fermentation  to  a  minimum.  Second,  It  must  be  col- 
lected in  covered  carts  or  wagons,  kept  as  air-tight  as  possible  to 
prevent  offensive  odors  escaping  along  the  streets.  Third,  A 
number  of  large  s'teel  tanks  or  digestors  of  a  strength  sufficient  to 
allow  an  internal  steam  pressure  of  one  hundred  pounds  per 
square  inch  receive  the  garbage,  forming  an  excellent  storage  for 
a  fluctating  delivery,  and  it  is  thoroughly  cooked  with  direct  steam 
until  all  of  the  dangerous  germs  are  killed,  the  greases  extracted 
and  the  whole  thoroughly  digested.  Fourth,  The  products  of  this 
digestion  are  now  utilized  as  follows:  The  contents  of  the  diges- 
tors are  emptied  out  in  continuous  filter,  which  separates  the  fibre 
from  the  liquid,  pressing  out  as  much  of  the  latter  as  possible. 
The  fibre  is  dried  and  may  be  burned  in  a  special  producer  or 
furnace,  with  the  production  of  large  quantities  of  useful  gas  and 
of  ammonia.  The  liquids  are  evaporated  to  get  rid  of  the  surplus 
water  after  the  valuable  greases  are  allowed  to  separate,  and  the 
resulting  sirupy  liquid  mixed  with  the  ashes  from  the  fibre  form 
valuable  fertilizing.  The  greases  are  refined  and  often  utilized 
in  the  production  of  toilets  soaps.  Many  of  the  best  known  soap 
makers  are  using  these  greases  from  the  reduction  works. 

Several  kinds  of  machinery  are  already  in  use  in  this  country 
to  produce  the  above  results.  It  only  needs  engineering  skill 
to  produce  valuable  products  from  the  waste,  and  there  is  more 
than  sufficient  carbon  in  the  dried  fibre  to  make  the  heat  and 
steam  needed  to  operate  the  plant. 

It  would,  therefore,  appear  that  the  reduction  of  waste  rather 
than  its  destruction  is  the  economical  process  to  develop,  and  in- 
cineration should  only  be  resorted  to  for  those  dry  wastes  which 
may  be  readily  utilized  as  fuel,  and  which  will  stand  storage  with- 
out fermentation. 

Mr.  George  Watson* — The  author  thanks  the  president  for  his 
very  kind  remarks.  It  is  quite  correct  that  Mr.  Horsfall  started 
his  destructor  business  with  the  steam  jet  for  forcing  the  draught. 
The  steam  jet,  as  pointed  out  somewhat  briefly  in  the  paper,  has 

*  Author's  closure,  under  the  Rules. 


1110  THE   BURNING  OF   TOWN   REFUSE. 

several  advantages,  among  which  it  may  be  again  mentioned,  that 
it  protects  the  grate  bars  and  other  iron  parts  of  the  furnace  from 
becoming  red  hot,  while'  at  the  same  time  in  many  cases  it  in- 
creases the  temperature  for  the  combustion  of  the  refuse.  But  it 
should  not  be  supposed  that  the  "  Horsf all  "  system  necessarily  in- 
volves the  use  of  steam  jets. 

In  many  cases  it  is  found  preferable  to  use  fans,  and  care  should 
always  be  taken  to  consider  the  exact  conditions  to  be  met  in 
making  the  selection. 

In  a  recent  instance  (at  Guernsey)  both  steam  jets  and  a  fan 
have  been  provided  in  a  "  Horsfall  "  destructor. 

This  arrangement  can  now  be  made  with  little  increase  of 
cost  over  the  fan  system,  and  it  is  one  which  offers  obvious  advan- 
tages. 

The  remarks  of  Mr.  A.  Saxon  serve  to  illustrate  the  difficulty  in 
which  the  author  was  placed  in  preparing  his  paper,  and  which  he 
endeavored  to  meet  by  confining  his  remarks  strictly  to  his  own 
experience.  He  also  tried  to  avoid  preferences  as  far  as  possible, 
and  in  indicating  the  advantages  of  the  "  Cellular "  type  of 
destructor,  he  expressed  his  own  opinion,  while  endeavoring  to 
avoid  undue  bias.  Moreover,  this  is  just  one  of  the  points  con- 
stantly debated  upon  which  the  author  considered  himself  free  to 
speak  his  mind,  for  the  reason  that  the  "  Cellular  "  system  is  no 
monopoly  of  any  one  firm,  but  is  free  to  be  adopted  by  all,  as  Mr. 
Saxon  well  knows.  The  author  is  not  aware  which  of  the  claims 
put  forward  for  the  "West  Hartlepool  Works  is  the  one  which  Mr. 
Saxon  considers  is  not  sustained.  He  can  only  say  that  he  is  quite 
unaware  of  any  inaccuracy  in  his  statement.  He  must  also  say 
that  in  his  opinion  the  results  obtained  at  West  Hartlepool  are 
comparable  to  those  obtained  on  either  of  the  "  Continuous- 
Grate  "  systems  at  present  on  the  market,  and  he  leaves  members 
to  make  their  own  comparison;  having  regard  to  steam  raising;  not 
only  on  trial,  but  in  every-day  working;  to  cost  of  labor  per  ton 
burned;  to  durability;  and  to  ease  of  repair.  As  to  the  expectation 
of  being  able  to  repair  one  cell  while  the  others  are  at  work  which 
Mr.  Saxon  thinks  unwarranted,  the  author  can  only  say  that 
under  his  own  supervision  such  repairs  are  frequently  made 
without  difficulty. 

While  congratulating  Mr.  Saxon  on  the  results  obtained  under 
test  at  "Woolwich,  the  author  may  be  allowed  to  say  that  there 
is  no  difficulty  in  burning  a  large  amout  of  refuse  per  square  foot 


THE   BURNING   OF   TOWN   REFUSE.  1111 

of  grate  per  hour,  either  in  the  "  Continuous-Grate  "  destructor, 
or  in  the  "  Cellular  "  destructor. 

It  is  a  question  simply  of  strength  of  blast,  and  of  frequency 
of  raking  over  and  of 'clinker ing.  In  other  words,  the  main  con- 
sideration is  that  of  the  labor  involved  in  the  operation.  It  is  the 
author's  experience  that  much  less  labor  is  involved  in  burning 
at  a  rate  of  30  pounds  per  square  foot  of  grate  per  hour  than  at 
TO,  while  the  clinker  produced  is  harder,  and  the  process  is  more 
complete,  clinkering  every  two  hours,  than  when  clinkering  at 
more  frequent  intervals. 

In  regard  to  the  remarks  of  Mr.  Trump,  the  author  supposes  it 
is  more  attractive  to  everybody  to  utilize  than  to  destroy.  But 
the  engineer  must  divest  himself  of  sentiment  and  reduce  the  ques- 
tion of  reduction  versus  destruction  to  figures. 

The  impression  gained  in  England  as  to  the  system  of  reduc- 
tion prevailing  in  the  United  States  is  that,  generally  speaking, 
they  do  not  pay,  or  at  least  that  they  wrill  not  continue  to  pay, 
and  further  it  is  practically  impossible  to  conduct  the  process 
without  creating  a  nuisance. 

Such  plants  are  often  the  subject  of  legal  injunction,  and  where 
they  escape  the  reason  seems  to  be  that  they  are  placed  at  a  con- 
siderable distance  from  dwellings. 

In  making  these  somewhat  sweeping  statements  the  author  is 
painfully  conscious  of  his  lack  of  experience,  but  he  is  merely 
reflecting  the  general  opinion  which  is  held  in  Europe,  which  may 
be  far  from  correct. 

He  does  not  understand  how  the  digesters  can  form  an  equaliz- 
ing storage  for  a  fluctuating  delivery,  unless  they  can  be  dis- 
charged while  under  pressure,  which  he  believes  is  not  the  case. 
Otherwise  they  must  be  completely  charged  and  then  sealed  up  till 
the  process  is  complete,  and  in  the  meantime  the  refuse  con- 
tinually arriving  must  be  otherwise  stored.  The  author's  own 
belief  is  that  refuse,  even  in  the  United  States,  is  constantly 
getting  less  valuable  for  any  purpose,  even  for  steam  raising,  as 
sanitary  science  progresses,  and  that  if  one-half  of  the  skill  em- 
ployed to  utilize  the  grease  from  the  refuse  were  applied  to  the 
utilization  of  the  clinker  from  the  destructor,  better  results  all 
round  could  be  obtained  from  a  centrally  situated  plant  without 
nuisance,  and  with  a  large  saving  in  cartage  to  put  to  the  credit 
of  the  destructor. 


JNTo.    1251 

THE  HIGH-PRESSURE  FIRE-SERVICE  PUMPS  OF 
MANHATTAN  BOROUGH,  CITY  OF  NEW  YORK 

DESCRIPTION  OF  PUMPS  AND  PUMPING  SYSTEM    WITH  RESULTS 

OF  TESTS 

BY  PROF.  R.  C.  CARPENTER,  ITHACA,  N.  Y. 
.  Member  of  the  Society 

The  object  of  this  paper  is  to  present  a  concise  description  of  the 
high-pressure  pumping  system  installed  for  fire  service  in  the  city  of 
New  York  and  the  results  of  a  test  of  the  pumping  machinery. 

2  The  system  protects  the  district  extending  north  from  City  Hall 
to  Twenty-fifth  Street,  and  east,  approximately,  from  the  North 
River  to  Second  Avenue.     It  comprises  about  55  miles  of  extra  heavy 
cast-iron  main,  from  12-in.  to  24-in.  in  diameter,  with  8-in.  hydrant 
branches;  and  two  pumping  stations  so  located  that  they  never  can 
be  in  the  center  of  a  conflagration.     At  the  present  time  the  pumping 
stations  have  a  combined   capacity  of   over   30,000  gal.   per   min. 
delivered  at  a  pressure  exceeding  300  Ib.  per  sq.  in. 

THE  SOURCE  OF  WATER  SUPPLY 

3  The  supply  of  water  is  ordinarily  obtained  from  the  water 
mains  of  the  city,  which  deliver  Croton  water  to  the  stations  at  a 
pressure  of  from  14  Ib.  to  40  Ib.  per  sq.  in.,  depending  upon  the 
demand  for  water  in  that  district.     Both  of  the  pumping  stations  are 
located  close  to  tidal  water  and  connections  are  made  so  that  sea 
water  can  be  obtained  in  case  of  difficulty  with  the  Croton  supply. 

4  The  advantage  of  the  Croton  water  over  salt  water  is  that  it  is 
less  likely  to  injure  goods,  and  as  the  amount  required  for  fire  purposes 
is  only  a  small  percentage  of  that  consumed  for  the  daily  supply  of  the 
city  its  use  for  fire  protection  makes  no  material  difference  from 
financial  or  insurance  standpoints.     As  this  is  a  matter  of  consider- 
able importance  data  upon  the  quantity  needed  are  given  in  the  next 
paragraph. 

Presented  at  monthly  meetings,  New  York  and  St.  Louis  (October  1909), 
of  THE  AMERICAN  SOCIETY  OF  MECHANICAL  ENGINEERS. 


438  HIGH-PRESSURE    FIRE-SERVICE    PUMPS 

WATER  REQUIRED  FOR  FIRE  PURPOSES 

5  The  general  impression  that  an  enormous  quantity  of  water  is 
required  for  fire  purposes  is  erroneous  as  shown  by  figures  furnished 
to  Chief  Engineer  I.  M.  de  Varona  by  the  fire  department  for  the 
Boroughs  of  Manhattan  and  Brooklyn,  years  1900, 1901, 1902,  1903  and 
1904.     These  give  the  average  quantity  of  water  used  for  fire  protec- 
tion during  these  years  in  the  Borough  of  Manhattan  as  74,010,803  gal. 
per  year,  of  which  31,056,928  gal.  was  river  water.     The  daily  aver- 
age use  of  Croton  water,  therefore,  for  the  above  five  years  was  117,- 
000  gal. 

6  For  the  Borough  of  Brooklyn  the  average  for  five  years  was 
43,705.568  gal.  of  which  19,010,928  gal.  was  river  water;  daily  aver- 
age, 67,000  gal. 

7  During  these  five  years  the  greatest  quantity  used  in    the 
Borough  of  Manhattan  was  99,000,000  gal.  in  1901,  which  included 
69,500,000  gal.  of  river  water,  leaving  29,500,000  gal.  for  Croton  water, 
and  Mr.  de  Varona  states   (Report  of  the  Department  of   Water 
Supply,  Gas  and  Electricity):  "Even  if  this  quantity  be  made  100,- 
000,000  gal.  per  year,  by  comparing  it  with  the  average  daily  con- 
sumption of  about  300,000,000  gal.  it  will  be  seen  that  the  total 
amount  used  for  fire  purposes  would  be  only  about  one-third  of  the 
amount  used  for  all  purposes  in  24  hr.,  forming,  therefore,  an  insignifi- 
cant percentage  of  the  total  consumption.     The  quantity  needed  for 
fire  purposes  (one-tenth  of  one  per  cent)  may  therefore  be  entirely 
neglected  as  a  factor  in  determining  the  water  supply  of  the  city. 

8  "The  capacity  of  each  of  the  pumping  stations  will  be  for  the 
present  15,000  gal.  per  min.  or  43,000,000  gal.  per  day  for  the  two  sta- 
tions.    By  the  installation  of  three  additional  units  in  each  station, 
for  which  provision  is  made,  this  capacity  can  be  increased  in  round 
numbers  to  69,000,000  gal.  per  day. 

9  "The  two  stations,  with  the  motors  and  pumps  as  installed, 
have  a  total  capacity  in  excess  of  that  of  all  the  fire  engines  in  the 
Boroughs  of  Manhattan,  the  Bronx  and  Brooklyn  working  under 
normal  conditions.     This  comparison  assumes  the  engines  to  work 
on  one  line  of  2J-in.  hose,  say  500  ft.  long,  under  a  pressure  of,  say 
200  lb.,  and  with  the  capacities  as  printed  in  the  official  blank  forms 
of  the  reports  of  the  fire  department.     It  should  furthermore  be 
remembered  that  provision  is  made  for  the  installation  of  still  another 
pumping  station." 


HIGH-PRESSURE   FIRE-SERVICE    PUMPS  439 

MOTIVE    POWER 

10  The  power  for  driving  the  pumps  is  transmitted  electrically 
from  several  of  the  electric  power  and  lighting  systems  located  on 
Manhattan  Island.     As  the  stations  of  systems  are  widely  separated 
and  any  or  all  of  them  are  available  for  motive  power  the  system  of 
electric  transmission  was  considered  more  reliable  in  the  case  of  a 
large  and  general  conflagration  than  power  plants  maintained  directly 
at  the  pumping  stations.     Each  station  is  provided  with  two  inde- 
pendent sets  of  transmission  lines  located  as  far  as  possible  beyond 
danger  or  injury  in  case  of  a  great  conflagration. 

11  The  cost  of  erecting  and  maintaining  an  independent  power 
plant  would  have  entailed  a  greater  annual  charge  than  the  cost  of 
the  electric  current;  consequently  the  present  arrangement  is  advan- 
tageous from  a  financial  standpoint. 

12  In  addition  to  the  charge  per  kilowatt  for  the  current  delivered 
there  is  a  charge  aggregating  $90,000  per  year  for  reserving  the  first 
right  of  use  for  the  necessary  generating  machinery  for  this  purpose. 
The  total  cost  of  maintenance  of  the  system  is  estimated  at  $170,000 
a  year,  which  amount  it  is  believed  will  be  saved  many  times  over  by 
a  reduction  in  insurance  premiums  now  paid  in  the  protected  district. 

13  The  electric  current  is  supplied  at  a  pressure  of  6600  volts 
from  the  following  stations  of  the  New  York  Edison  Company,  hav- 
ing the  capacity  indicated:  53  Duane  Street,  7600  kw.;  115  East  12th 
Street,  1700  kw.;  45  West  26th  Street,  400  kw.;  140th  Street  and 
Ryder  Ave.,  4000  kw.;  Waterside  Stations  No.  1  and  No.  2,  196,700 
kw.     In  addition  there  are  feeders  extending  to  the  Brooklyn  Edison 
Company  stations  which  can  be  called  on  in  case  of  an  emergency 
demand. 

14  The   pumping   stations   are    connected   to    18   sub-stations, 
equipped  with  rotary  converters  and  storage  batteries,  aggregating 
a  capacity  of  124,000  ampere  hours  at  135  volts,  an  enormous  reserve. 

15  Each  station  is  connected  with  the  main  stations  of  the  Edison 
Company  by  two  250,000  c.m.  three-phase  cables  laid  in  ducts,  and 
two  independent  reserve  feeders  extend  to  the  sub-station  system 
of  the  Edison  Company.     With  all  these  precautions,  interruption 
of  the  power  supply  would  seem  a  physical  impossibility. 

THE  DISTRIBUTION  SYSTEM 

16  The  following  information  upon  the  distribution  system  is  taken 
largely  from  the  department  report  of  Chief  Engineer  de  Varona 


440 


HIGH-PRESSURE    FIRE-SERVICE    PUMPS 


FIG.  1    SHOWING  LOCATION  OF  STATIONS  AND  AREAS  COVERED  BY  HIGH- 
PRESSURE  PUMPING  SYSTEM 

THE    AREA    INDICATED    IS  SERVED  BY  A  SYSTEM    OP  MAINS    RANGING    FROM  24    IN.   TO    12  IN.    IN 
DIAMETER  WITH  8-IN.   HYDRANT  CONNECTIONS 


HIGH-PRESSURE    FIRE-SERVICE    PUMPS  441 

for  1905.  Fig.  1  shows  the  system  to  be  bounded  by  mains  laid  on 
the  north  through  Twenty-third  Street;  on  the  east,  through  Broad- 
way to  Fourteenth  Street,  through  Fourteenth  Street  to  Third 
Avenue,  down  Third  Avenue  to  the  Bowery,  down  the  Bowery  to 
Chambers  Street;  through  Chambers  Street  on  the  south  to  West 
Street;  and  on  the  west  through  West  Street. 

17  The  area  actually  protected  is  considerably  greater  than  this 
as  hose  can  be  extended  over  a  zone  600  ft.  wide  beyond  the  limits 
of  the  mains. 

18  This  district  was  selected  as  that  in  which  the  fire  losses  were 
the  greatest  and  which  most  urgently  needed  fire  protection.     Plans 
have  been  prepared  for  the  extension  of  the  system  southerly  to  the 
Battery,  easterly  as  far  as  the  East  River,  and,  if  necessary,  northerly 
as  far  as  Fifty-ninth  Street,  by  the  simple  extension  of  the  mains 
and  probably  the  erection  of  a  third  pumping  station. 

19  The  pipes,  castings  and  hydrants  were  tested  at  a  pressure  of 
450  Ib.     The  specified  allowance  for  leakage  in  a  10-min.  test  was 
at  the  rate  of  4  gal.  in  24  hr.  for  each  lineal  foot  of  pipe  joint,  equiva- 
lent to  a  leakage  of  487,000  gal.  for  the  whole  system  in  24  hr.,  which  is 
somewhat  over  one  per  cen  t  of  the  total  specified  pumping  capacity  now 
installed.     The  actual  leakage  on  test  was  at  the  rate  of  264,000  gal. 
per  day  or  about  six-tenths  of  one  per  cent  of  the  pumping  capacity. 
Considering  the  difficulties  of  construction  and  the  high  pressure,  the 
results  attained  were  remarkable  and  reflect  great  credit  on  the 
engineer  in  charge. 

20  There  are  sufficient  hydrants  so  that  if  a  block  were  on  fire  60 
streams  of  500  gal.  per  min.  each,  or  the  full  capacity  of  both  stations, 
could  be  concentrated  on  a  block  with  a  length  of  hose  not  exceeding 
400  ft.  to  500  ft.,  assuming  the  use  of  3-in.  hose  and  li-in.  nozzles. 

21  The  layout  of  the  mains  at  the  stations  both  for  suction  and 
delivery  is  on  the  loop  system;  that  is,  the  supply  can  be  taken  from 
either  one  of  two  mains,  and  the  discharge  is  through  either  one  or 
both  of  two  mains.     With  this  system  even  the  breakdown  of  one 
of  the  discharge  mains  at  the  station  would  only  slightly  reduce  the 
pressure  at  the  fire  and  would  not  affect  the  capacity  of  the  station, 
as  the  pumps  would  be  capable  of  forcing  their  full  discharge  through 
the  short  length  of  a  single  24-in.  main  if  made  necessary  by  such  an 
accident. 

22  The  mains  are  of  cast-iron,  bell  and  spigot  pipe,  of  the  thick- 
nesses given  in  the  following  table: 


442  HIOH-PBESSUKE    FIRE-SERVICE    PUMPS 

Unit  Tensile  Strain 

Size  of  Pipe  Thickness  with  300  Ib.  pres- 

Inches  Inches  sure                Factor  of  Safety 

24  1*  1920  0.4 

20  1*  2000  10.0 

16  H  1920  10.4 

12  1  1800  11.1 

8*  I  1371  14.6 

*  Used  only  for  hydrant  branches. 

SUPPLY  PIPING 

23  At  the.  South  Street  Station  the  fresh  water  supply  is  derived 
from  two  30-in.  lines,  one  connected  at  Chestnut  Street  to  the  36-in. 
line  on  Madison  Street,  and  the  other  connected  at  Pike  Street  to 
the  36-in.  line  on  Division  Street.     These  two  main  feeders,  to  which 
the  two '30-in.  lines  are  connected,  increase  to  48  in.  in  diameter  and 
extend  independently  and  directly  to  the  Central  Park  Reservoir  and 
are  also  reinforced  by  connections  with  the  main  feeders  in  this  sec- 
tion of  the  city. 

24  An  auxiliary  salt-water  supply,  consisting  of  two  36-in.  pipes 
about  140  ft.  long,  brings  the  salt  water  from  the  East  River  to  a 
suction  chamber  located  directly  in  front  of  the  pumping  station. 
This  suction  is  so  constructed  that  the  pipes  are  always  below  mean 
low  water,  thus  insuring  a  supply  at  all  times  and  avoiding  the  possi- 
bility of  a  break  in  the  suction  caused  by  air  getting  into  the  suction 
lines.     On  the  river  end  of  this  suction  there  are  constructed  heavy 
bulkhead  screens  and  in  the  suction  chamber  are  two  sets  of  bronze 
screens  which  are  readily  accessible  for  cleaning.     From  the  suction 
chamber  there  are  taken  two  30-in.  flanged  mains  to  the  duplicate 
set  of  mains  in  the  pumping  station  proper.     The  vacuum  in  these 
30-in.  pipes  is  maintained  by  automatic  electric  vacuum  pumps 
located  on  the  pump  room  floor  of  the  station. 

25  At  the  Gansevoort  Street  Station  the  fresh-water  supply  is 
derived  from  two  30-in.  mains,  one  connected  at  Twelfth  Street  to 
the  48-in.  line  on  Fifth  Avenue,  which  runs  direct  to  Central  Park 
Reservoir,  and  the  other  connected  to  the  36-in.  line  on  Ninth  Ave- 
nue at  Little  West  12th  Street,  which  increases  to  a  48-in.  line  and  runs 
also  direct  to  the  Central  Park  Reservoir.    These  two  main  feeders, 
in  addition  to  having  their  supplies  direct  from  Central  Park  Reser- 
voir, are  also  reinforced  by  connections  with  the  main  feeders  in  this 
section  of  the  city. 


HIGH-PRESSURE    FIRE-SERVICE    PUMPS  443 

26  The  salt-water  suction  lines  for  this  station  are  practically 
identical  with  those  for  the  South  Street  Station  except  that  the 
36-in.  lines  from  the  North  River  to  the  station  are  650  ft.  long. 

PUMPING    STATIONS 

27  The  two  stations,  known  as  the  Gansevoort  pumping  station, 
located  near  Gansevoort  Market  on  the  North  River,  and  the  South 
Street  station,  located  on  the  corner  of  Oliver  and  South  Streets  near 
the  East  River,  are  identical  in  construction  and  equipment.     The 
buildings  are  of  simple  design,  of  steel  fire-proof  construction,  with 
concrete  foundations.     The  Gansevoort  Street  building,  which  is 
typical  of  both,  is  one  story  high  with  basement,  63  ft.  8  in.  by  97  ft. 
4  in.     Each  station  is  large  enough  for  eight  pumping  units. 

MACHINERY 

28  There  are  now  five  units  in  each  station  consisting  of  Allis- 
Chalmers   five-stage   centrifugal   pumps   driven   by   Allis-Chalmers 
induction    motors    and    the    necessary   auxiliary    machinery.     The 
motors  and  pumps  are  alike  and  their  parts  are  interchangeable. 

29  The  pumps"each  have  a  specified  capacity  of  3000  gal.  per  min. 
of  sea-water,  working  with  a  suction  lift  of  20  ft.  and  a  delivery 
pressure  of  300  Ib.  per  sq.  in.     The  actual  capacity  as  indicated  by  a 
24-hr,  test  was  about  30  per  cent  in  excess  of  that  specified.     The 
original  specifications  contemplated  the  use  of  six-stage  pumps,  with 
the  expectation  that  sea-water  would  be  used  at  each  fire.     Because  of 
the  facts  already  referred  to  (Par.  4),  that  the  relative  amount  of  water 
required  for  fire  purposes  is  insignificant  and  that  sea-water  may  do 
considerably  more  damage  to  goods  than  fresh  water,  a  change  in  the 
specifications  was  agreed  to,  whereby  the  pumps  should  work  at  best 
efficiency  when  receiving  water  from  the  Croton  mains  at  a  pressure 
on  the  intake  side  varying  from  15  Ib.  to  40  Ib.  per  sq.  in. 

30  To  meet  this  new  condition  the  pumps  were  all  built  with  five 
stages.     All  the  sea  connections  and  priming  machinery  as  originally 
contemplated  were  installed,  so  that  sea-water  can  be  pumped  into 
the  mains  whenever  desired.     The  effect  of  the  change  is  merely  to 
reduce  the  pressure  head  slightly  in  case  sea-water  is  used. 

ARRANGEMENT   OF   MACHINERY 

31  The  floor-plans  of  the  buildings  and  general  layout  of  machin- 
ery, piping,  switchboards,  etc.,  are  shown  in  Fig  2.     As  will  be  seen 


444 


HIGH-PRESSURE    FIRE-SERVICE    PUMPS 


FIG.  2     PLAN  AND  ELEVATION  SHOWING  ARRANGEMENT  OP  HYDRAULIC  AND 
ELECTRICAL  APPARATUS  IN  PUMPING  STATIONS 


HIGH-PRESSURE    FIRE-SERVICE    PUMPS 


445 


space  is  provided  for  three  additional  units.  Working  detail  plans  of 
the  machinery  were  furnished  by  the  contractor.  The  arrangement 
shown  in  Fig.  2  is  the  same  for  both  stations,  the  only  difference  being 
that  the  switchboard  and  office  in  the  South  Street  station  are  on 
different  sides  of  the  building  as  compared  with  the  Gansevoort 
Street  station. 

32  The  motors  and  pumps,  with  suction  and  delivery  branches, 
are  located  on  the  main  floor  of  the  pump  room.  The  switchboard 
and  switchboard  apparatus  are  placed  in  an  enclosed  two-story  and 
basement  gallery. 


FIG.  3     INTERIOR  VIEW  OF  STATION 

33  The  four  high-tension  feeders  and  all  other  wires  entering  the 
building  are  brought  in  through  the  gallery  basement.     All  terminal 
work  on  the  entering  wires  is  located  in  the  basement.     On  the  first 
floor  of  the  gallery,  which  is  approximately  on  the  same  level  as  the 
pump-room  floor,  are  placed  the  oil  switches,  with  their  controlling 
and  protective  devices,  fire-proof  cells  and  compartments. 

34  The  operating  switchboard  is   conveniently  located   in  the 
enclosing  wall  of  the  gallery,  and  is  so  placed  as  to  allow  a  man 
standing  on  the  pump-room  floor  to  perform  all  the  operations  neces- 
sary for  controlling  the  apparatus  in  the  station.     The  bus  bars, 


446  HIGH-PRESSURE    FIRE-SERVICE    PUMPS 

with  their  fireproof  compartments,  are  placed  on  the  second  floor  of 
the  gallery. 

MOTORS  FOR  CENTRIFUGAL  PUMPS 

35  The  motors  are  of  the  constant-speed,  wound-rotor  induction 
type ,  3-phase,  25-cycle,  6300-volt  to  6600-volt,  designed  to  operate 
at  about  740  r.p.m.     Each  pump  is  direct-connected  to  its  motor 
by  a  flexible  coupling  which  takes  care  of  any  variation  from  align- 
ment.    In  starting,  an  iron   grid   resistance   is  connected  in   the 
secondary  circuit  and  gradually  cut  out  by  means  of  a  handwheel 
on   the  motor  switchboard  panel.     When  the  resistance  is  all  cut 
out   the   rotor    is    automatically   short-circuited   and  operated  by 
specially   constructed  solenoids    through   a   small  switch  mounted 
directly  on   the    shaft    of    the   handwheel  above  referred  to.     An 
interlocking  arrangement  prevents  the  operator  from   closing  the 
switch  connecting  the  motor  to  the  line  while  the  motor  is  short- 
circuited. 

36  The  specifications   required  the   motors  to   have   sufficient 
starting  torque  to  attain  full  speed  between  30  sec.  and  45  sec.  after 
starting,  with  a  current  not  exceeding  150  per  cent  of  that  used  when 
the  motor  is  working  under  full  speed.     Each  motor  was  required  to 
develop  not  less  than  800  b.h.p.  when  using  current  of  6300  volts, 
25  cycles,  and  under  these  conditions  to  have  an  efficiency  not  less 
than  92  per  cent,  a  power  factor  not  less  than  93  per  cent,  and  a 
motor  slip  not  in  excess  of  2  per  cent.     At  three-quarters  load  the 
efficiency  was  not  to  be  less  than  92  per  cent  and  the  slip  not  to  exceed 
1.5  per  cent.     It  was  specified  that  the  temperature  of  the  motors 
should  not  rise  more  than  40  per  cent  on  a  24-hr,  test  at  full  load, 
when  measured  by  a  thermometer,  the  air  in  the  room  being  25  deg. 
cent. 

37  Prof.  Geo.  F.  Sever  of  Columbia  University  tested  two  of  the 
motors  in  the  shops  of  the  contractor  and  found  them  to  meet  the 
specifications  and  to  have  a  full-load  efficiency  of  93.2  per  cent.     The 
other  motors  were  inspected  and  found  to  be  alike  and  were  assumed 
to  have  the  same  efficiency.     The  motors  were  also  tested  for  tempera- 
ture rise  at  the  time  of  the  official  test  to  be  described  later. 

MOTORS  FOR   AUXILIARIES 

38  Direct-current  motors  of  240  volts  are  provided  to  operate  the 
various  gate  valves  in  the  station  and  the  piston  pumps  employed  for 
maintaining  a  vacuum  on  the  salt-water  suction  lines. 


g  HIGH-PRESSURE    FIRE-SERVICE    PUMPS  447 

PUMPS 

39  As  previously  stated  the  pumps  were  finally  constructed  with 
five  stages,  each  to  give  a  pressure  of  somewhat  over  60  Ib.  per  sq. 
in.,  making  the  combined  pressure  of  the  five  stages  about  300  Ib. 
per  sq.  in.  above  the  intake  pressure,  which  is  the  maximum  working 
pressure  of  the  stations  at  normal  speed  of  740  r.p.m.     This  type  of 
pump  is  the  simplest  now  on  the  market  for  pumping  water  either 
against  a  high  head  or  low  head,  and  this  simplicity  was  the  deciding 
factor  which  led  to  the  selection  of  this  style  of  machinery. 

40  The  pumps  are  water-balanced  by  a  piston  connected  to  the 
last  "impeller  and  upon  which  the  water  pressure  acts,  but  should 
any  additional  end-thrust  occur,  it  would  be  taken  up  by  the  ball 
bearing  provided  in  the  outboard  bearing.     This  ball  bearing  consists 
of  two  rings  of  IJ-in.  diameter  steel  balls  and  is  water-cooled.     The 
balancing  piston  is  fitted  very  loosely  in  order  to  keep  the  friction 
losses  small,  and  as  a  result  a  considerable  amount  of  water  leaks  past 
it  into  a  chamber  at  the  end  of  the  pump,  which  is  provided  with  a 
discharge  pipe  and  valve  leading  into  the  suction.     By  adjusting 
the  valve  in  this  pipe  the  difference  of  pressures  on  the  piston  can  be 
regulated  as  desired.     The  bearings  are  of  the  ring-oiled  type  and  are 
separated  from  the  pump  casing  by  packing  glands  which  prevent 
foreign  matter  from  entering  the  bearings.     The  impellers  are  of 
bronze  and  the  shaft  of  forged  steel.     All  parts  of  the  runners  and 
diffusion  vanes  are  thoroughly  lubricated  by  oil  cups  on  the  base  of 
the  pumps.    A  feature  is  the  wide  base,  shown  in  Fig.  4,  which  allows 
the  pump  barrel  to  set  low,  giving  stability. 

41  Each  combined  unit  is  equipped  with  automatic  and  hand 
control.     The  pumps  are  kept  primed  for  instant  service  and  the 
simple  operation  of  a  switch  on  the  main  switchboard  starts  the 
machine  and  gives  full  pressure  in  about  30  sec. 

PRESSURE -REGULATING   VALVES 

42  A  combined  regulating  and  relief  valve  is  interposed  between 
the  discharge  pipe  and  the  suction  pipe  of  each  pump,  and  set  to  regu- 
late the  discharge  of  each  pump  to  any   predetermined   pressure. 

43.  When  the  Volume  of  the  water  discharged  by  the  pump  is  in 
excess  of  that  forced  into^the  system,  this  valve  acts  as  a  relief  valve 
and  by-passes  this  excess  ^into  the  suction  to  the  pump,  the  pres- 
sure on  the  main  distribution  system  remaining  at  the  predetermined 


448 


HIGH-PRESSURE    FIRE-SERVICE    PUMPS 


point.  When  no  water  is  forced  into  the  distribution  system  all  of  the 
water  discharged  from  the  pump  is  then  by-passed  into  the  suction. 
44  The  'pressure-regulating  valves  were  made  by  the  Ross  Valve 
Mfg.  Co.,  of  Troy,  N.  Y.,  and  much  of  the  practical  success  of  the 
station  has  been  due  to  the  accuracy  with  which  they  maintain  any 
desired  pressure. 


FIG.  4      MULTISTAGE  PUMP,  CAPACITY  3000  GAL.  PER  MIN.;  MAXIMUM  HEAD, 

300  LB.  PER  SQ.  IN. 


PRIMING    APPARATUS    FOR    SALT-WATER    SUCTION    LINES 

45  The  priming  apparatus  In  each  station  consists  of  three  motor- 
driven  vacuum  pumps,  each  arranged  to  maintain  automatically  a 
vacuum  of  26  in.  in  the  suction  lines.     These  pumps  are  of  the  piston 
single-action  type,  one  having  a  displacement  capacity  of  300  cu.  ft. 
per  min.  for  a  piston  speed  of  200  ft.  per  min.  and  each  of  the  others 
a  displacement  capacity  of  50  cu.  ft.  with  a  piston  speed  of  160  ft. 
per  min. 

46  An  air-collecting  chamber  is  connected  to  each  of  the  salt- 
water suction  lines  and  equipped  with  water-gage  glass  and  vacuum 
gage.     The  air-suction  piping  between  the  air  chambers  and  the  air 
pumps  is  provided  with  a  veitical  loop  sufficiently  high  to  prevent 


HIGH-PRESSURE    FIRE-SERVICE    PUMPS 


449 


450  HIGH-PRESSURE    FIRE-SERVICE    PUMPS 

water  being  carried  over  to  the  pumps.     The  air  pumps  are  inter- 
connected to  each  air  chamber. 

VENTURI   METERS 

47  Venturi  meters  for  measuring  the  discharge  of  water  from  the 
station  and  from  one  main  to  the  other  were  set  by  the  contractor  on 
each  discharge  main  and  on  the  cross-connecting  main.     The  meters 
of  the  discharge  main  are  24  in.  in  diameter  and  on  the  cross-over 
main  12  in.  in  diameter.     These  meters  were  standardized  under  the 
direction  of  F.  N.  Connet,  Manager    of  the  Venturi  Meter  Sales  De- 
partment  of  the  Builders  Iron  Foundry,  Providence,  R.  L,  and  were 
provided  with  dial-indicating  gages  and  also  chart-recorders  gradu- 
ated to  indicate  the   flow  in  gallons  per  minute;  and  in  addition 
with  an  integrating  meter  which  registers  the  total  flow  in  gallons. 

48  The  readings  during  the  test  were  taken  by  a  mercury  mano- 
meter, graduated  to  show  the  capacity  in  thousands  of  gallons  per 
minute.     For  this  purpose  a  Venturi  manometer  was  attached  with  a 
temporary  connection  to  each  of  the  24-in.    Venturi  tubes.     The 
manometer  gave  essentially  the  same  reading  as  the  indicating  dial 
on  the  main  register. 

49  The  Venturi  manometer  is  practically  a  tube  partly  filled  with 
mercury,  one  side  of  which  communicates  with  the  upstream  pressure 
chamber  of  the  meter  tube,  while  the  other  communicates  with  the 
throat-pressure    chamber.     The    connections   with   the    manometer 
are  indicated  in  the  diagram,  Fig.  6. 

50  The  sketch  shows  a  24-in.  high-pressure  meter  tube,  its  register- 
indicator-recorder  and  manometer.     The  instruments  and  meter  tube 
are  drawn  to  scale,  but  in  the  pumping  station  the  meter  tube  is  about 
75  ft.  distant  from  the  instruments. 

TESTS  OF   MACHINERY 

51  The  specifications  for  the  pumping  system  provided  for  an 
endurance  test  of  each  motor  and  pump  lasting  24  hr.  without  stop, 
during  which  time  the  capacity  and  efficiency  of  the  pumps  and 
motors  were  to  be  determined.     The  tests  were  to  be  in  charge  of  an 
expert  appointed  by  the  commission. 

52  The  specifications  provided  for  making  the  test  with  sea  water, 
but  this  was  later  changed  to  a  test  with  Croton  water  under  the  con- 
ditions of  actual  use.     In  view  of  this  change  the  contractor  increased 
the  efficiency  guarantee  from  70  to  71  per  cent. 


HIGH-PRESSURE   FIRE-SERVICE    PUMPS 


451 


452  HIGH-PRESSURE    FIRE-SERVICE    PUMPS 

53  The  original  specifications  called  for  a  capacity  of  3000  gal.  of 
sea  water  per  minute  against  a  discharge  pressure  of  300  Ib.  per  sq. 
in.  and  a  suction  lift  not  exceeding  20  ft.     The  total  increment  of 
pressure  is  equivalent  to  308.66  Ib.  from  the  intake  to  the  delivery 
side.     The  Croton  pressure  varies  at  the  stations  in  different  parts 
of  the  day  from  about  40  Ib.  to  13  Ib.  per  sq.  in.  and  is  affected  by  the 
amount  of  water  being  drawn  from  the  mains.     Consequently,  to 
meet  the  requirements,   the   delivery   pressure   would   need   to  be 
308.66  Ib.  in  excess  of  the  intake  pressure.     There  is  also  a  further 
correction  from  the  fact  that  sea  water  is  heavier  than  fresh  water 
and  this  correction  under  maximum  conditions  might  amount  to  2.5 
per  cent. 

54  The  specifications   further  provided   that  the   brake   horse- 
power developed  by  the  motors  under  test  should  be  computed  from 
the  electrical  energy  supplied  to  them,  corrected  for  the  efficiency 
of  the  motors  as  determined  by  the  test.     They  further  provided  that 
if  the  aggregate  of  all  stops  exceeded  one  hour  for  any  motor  the  test 
for  capacity  for  such  motor  was  to  be  run  over  again  for  a  period 
of  24  hr. 

55  The  specifications  also  provided  that  the  pumping  capacity  of 
the  apparatus  and  the  efficiency  of  the  pumps  should  be  based  on 
the  minimum  rate  of  pumping  during  any  eight  consecutive  hours  of 
the  endurance  test,  during  which  none  of  the  motors  were  stopped. 

56  The  discharge  of  the  pumps  was  determined  by  the  reading 
of  the  Venturi  meters,  one  of  which  was  located  in  each  discharge 
line.     These  readings  were  under  the  direction  of  F.  N.  Connet,  and 
were  checked  by  observers  representing  the  contractors  and  also  the 
city. 

57  The  modified  specifications  also  required  that  the  efficiency  of 
each  pump  should  be  not  less  than  70  per  cent  and  its  capacity  not 
less  than  3000  gal.  of  sea  water  when  lifted  to  a  pressure  equivalent 
to  308.66  Ib.     To  determine  whether  the  requirement  was  met,  a 
separate  test  of  each  pump  was  required. 

58  The  efficiency  of  the  pumps  was  computed  by  dividing  the 
horse-power  output  of  the  pumps    by   the    horse-power   input  as 
received  from  the  motors.     The  horse-power  input   was  computed 
as  follows: 

total  watts  ,x 

h.p.  input   =       — X   efficiency  of  motors  (93.2  per  cent) 


HIGH-PRESSURE    FIRE-SERVICE    PUMPS  453 

The    horse-power    output  was    computed    as    follows:    h.p.  output 
wt.  per  gal.  (8.34)  X  2.31  head  in  pounds  X  no.  of  gal.  per  min. 

"33,000 

SOUTH  STREET  STATION  TEST 

59  The  test  of  the  South  Street  Station  was  begun  at  12:30  p.m. 
on  September  2,  1908,  after  about  2  hr.  of  preliminary  running  for 
the  purpose  of  adjusting  the  delivery  pressure;  it  was  continued  with- 
out interruption  for  24  hr.     With  the  exception  of  a  short  stop  of 
motor  No.  2  which  was  shut  down  from  2:11  to  2:41  a.m.,  September 
3,  to  remedy  a  slight  defect  in  the'insulation  of  the  field  coils,  no  pump 
was  stopped.     During  the  time  No.  2  was  stopped  the  pressure  on  the 
delivery  mains  fell  to  about  300  Ib. ;  during  the  remainder  of  the  test 
the  pressure  was  maintained  at  or  above  the  contract  requirement, 
as  will  be  noted  by  consulting  the  last  column  of  Table  1. 

60  The  average  results  for  each  hour  for  the  24-hr,  test  of  all  four 
motors  are  given  in  Table  2.     The  smallest  delivery  for  eight   con- 
secutive hours  occurred    at  the  last  part   of  the   test,   when    the 
average  capacity,   as  shown  by  the  readings,  was  18,447  gal.  per 
min.,  and  the  average  efficiency  was  72.2  per  cent.     During  this 
time  the  average  pressure  pumped  against  was  314.5  Ib.,  or  an  excess 
of  about  6  Ib.  over  contract  requirement. 

61  It  will  be  noted  from  the  last  column  of  Table  2  that  there  is 
considerable  variation  in  the  efficiency;  that  during  the  first  hour  the 
efficiency  was  less  than  70. per  cent,  whereas  during  the  third  and 
fourth  hours  the  efficiency  ^exceeded  75  per   cent.    This  variation 
in  efficiency  was  doubtless  caused  by  variation  in  the  amount  of  water 
by-passed  from  the  pressure  to  the  suction  side  of  the  pump  over  the 
balanced  piston  and  through  the  bearings,  and  possibly  during  the 
first  hour  by  the  discharge  of  some  water  through  the  relief  valve 
which  was  pumped  but  not  metered.     The  valves  for  regulating  the 
differential  pressure  on  the  balance  pistons  were  nearly  closed  during 
the  third,  fourth  and  fifth  hours  of  the  South  Street  Station  test,  but 
were  opened  the  normal  amount  for  the  remaining  portion  of  the 
test.     The  amount  of  water  which  for  maximum  difference  of  pres- 
sure may  leak  around  the  balance  piston  of  any  pump  without  passing 
through  the  meter  could  not  be  accurately  determined  but  was  esti- 
mated to  be  in  excess  of  4  per  cent.     Hence  it  appears  that  slight 
changes  in  the  opening  of  the  valve  controlling  the  differences  of  pres- 
sure at  this  piston  must  materially  affect  the  efficiency.     The  normal 


454 


HIGH-PRESSURE    FIRE-SERVICE    PUMPS 


opening  of  this  valve  appears  to  correspond  to  an  efficiency  of  about 
72.5  per  cent. 

62  During  the  test  of  the  South  Street  Station  all  the  bearings 
ran  cool  with  the  exception  of  those  on  No.  6  pump,  which  heated  up 
during  the  third  and  fourth  hours  but  were  brought  to  a  normal  con- 
dition without  stopping  the  pump  or  reducing  its  load  by  the  appli- 
cation of  lubricants  and  cooling  water. 

TABLE  1     HOURLY  AVERAGE  OF  READINGS  OF  DISCHARGE  AND  INJECTION 

GAGES  ON  PUMPS 

*SOUTH  STREET  PUMPING  STATION,  SEPTEMBER  2  AND  3,  1908 


Hour 

PUMP  No.  6 

PUMP  No.  4 

PUMP  No.  2 

PUMP  No.  1    PUMP  No.  3 

!  Net 
AVERAGE      „ 
Pres- 

Disc. 

Inj. 

Disc. 

Inj. 

Disc. 

Inj. 

Disc. 

Inj. 

Disc. 

Inj. 

Disc. 

sure 
Iiij.       Lb. 

12:30-  1:15  335.0 

21.8 

332.3 

22.6 

329.8 

22.5 

331.0 

24.0   332.9 

23.3 

332.2 

22.8   309.4 

1:30-  2:15!  347.2 

20.9 

347.0 

22.2 

345.5 

22.1 

343.8 

22.6   346.2 

22.1 

345.9    22.0   323.0 

2:30-  3:15  345.0 

20.9 

343.8 

21.8 

342.8 

22.1 

341.0 

22.5   343.4 

21.8 

343.2    21.8   321.4 

3:30-  4:00  344.2 

20.9 

343.8 

21.9 

340.3 

22.3 

339.8 

22.6   342.2 

21.9 

342.1    21.9   320.2 

4:30-  5:00   341.7 

21.1 

341.8 

21.9 

340.8 

22.6 

339.3 

23.1 

342.2 

22.4 

341.2 

22.2   319.0 

5:30-  6:00 

336.2 

22.4 

336.3 

22.9 

335.3 

23.8 

333.3 

25.3 

335.7 

23.6 

335.4   23.6   311.8 

6:30-  7:00 

337.2 

24.4 

336.8 

24.9 

334.8 

25.3 

333.8 

26.3 

335.7 

24.9 

335.  7!  25.2   310.5 

7:30-  8:00  339.7 

25.1 

337.8 

25.9!  335.8 

26.6   334.8 

27.3 

337.7 

25.9 

337.2    26.2    311.0 

8:30-  9:00 

341.2 

26.6 

339.3 

26.9 

338.3 

27.3   337.3 

28.8 

338.7 

27.1 

339.0   27.3   311.7 

9:30-10:00'  344.7 

27.6 

342.8 

27.9 

341.8 

28.6 

343.3 

29.3 

344.7 

27.9 

343.5   28.3    315.2 

10:30-11:00  342.2 

28.9 

341.3 

29.1 

340.3 

29.3 

340.8 

30.8 

342.7 

29.6 

341.5   29.5;  312.0 

11:30-12:00 

343.7 

30.4 

344.3 

29.9 

343.3 

30.3 

342.3 

32.1 

343.7 

30.6 

343.51  30.7;  312.8 

12:30-  1:00  345.7 

30.6 

347.3 

30.1 

347.3 

30.8 

345.8 

32.6 

347.9 

31.4 

346.8   31.1!  315.7 

1:30-  2:15 

334.0 

30.9 

334.5 

30.6* 

332.6 

33.1 

333.9 

31.4 

333.7    31.5   302.2 

2:30-  3:00  332.4 

31.1 

331.0 

30.9 

330.8 

32.8 

332.2 

31.6 

331.6   31.  6  300.0 

3:30-  4:00  349.2 

31.4 

348.3 

31.1 

346.3 

31.6   347.3 

33.3 

349.2 

31.6 

348.1 

31.8   316.3 

4:30-  5:00!  347.2 

31.1 

346.8 

30.9 

346.3 

31.3   345.8 

32.8  349.4 

31.4 

347.1 

31.5   315.6 

5:30-  6:00 

346.7 

28.6 

346.3 

28.4 

345.3 

29.3   345.3 

30.6 

348.2 

29.4 

346.4 

29.3   317.1 

6:30-  7:00  342.2 

27.6 

342.3 

25.4 

340.3 

26.1   340.3 

27.1 

341.2 

26.1 

341.3 

26  5  314.8 

7:30-  8:00  332.7 

21.6 

332.3 

22.1 

330.3 

22.6   329.3 

24.1 

331.2 

22.6 

331.2 

22.6  308.6 

8:30-  9:00 

332.7 

20.9 

332.3 

21.4  331.3 

22.1   329.3 

22.6 

331.2 

21.6 

331.4 

21.7!  309.7 

9:30-10:00 

331.7 

20.6 

332.3 

20.9 

328.8 

21.8 

328.3 

22.8   331.2 

22.1 

330.5 

21.6   308.9 

10:30-11:00  334.2 

21.4 

336.8 

21.6 

332.8 

22.3 

331.8 

23.3 

336.2 

22.4 

334.4 

22.2   312.2 

11:30-12:30 

336.0 

21.9 

338.0 

21.9 

333.6   22.6 

334.0 

23.8 

337.7 

22.6 

335.9 

22.fi   313.3 

I 

Readings  corrected  for  error  of  gage  and  to  center  of  pumps. 

*  Pump  No.  2  shut  down  from  2:11  to  2:41  on  account  of  motor. 

63  It  will  be  noted  from  Table  2  that  the  average  results  of  the 
24-hr,  test  of  the  South  Street  Station  exceeded  the  contract  require- 
ments in  capacity,  pressure  head  and  efficiency. 

64  The  horsepower  delivered  by  the  motors  during  the  test  aver- 
aged for  the  24  hr.  about  920  or  about  15  per  cent  above  rating,  with- 
out excessive  heating. 


HIGH-PRESSURE    FIRE-SERVICE    PUMPS 


455 


TABLE  2    COMPUTATION  OF  PUMP  EFFICIENCIES 
SOUTH  STREET  PUMPING  STATION,  SEPTEMBER  2  AND  3,  1908 


Hour 
Beginning 

r.p.m. 

. 

Total  kw. 
per   hr. 

Total  h.p. 
from 
motors 
(input) 

Gal.  per 
min. 

Net 
pressure 
Ib. 

h.p. 
delivered 

Efficiency 
per  cent 

12:30  p.m. 

3875 

4841.4 

18334 

309.4 

3311.6 

68.6 

1:30 

757.0 

3851 

4811.4 

18634 

323.9 

3523.6 

73.2 

2:30 

755.0 

3829 

4784.0 

19217 

321.4 

3605.7 

75.4 

3:30 

3819 

4771.5 

19220 

320.2 

3592.8 

75.3 

4:30 

755.0 

3811 

4761.5 

19145 

319.0 

3565.4 

75.0 

5:30 

3837 

4794.0 

18995 

311.8 

3457.6 

72.1 

6:30 

755.0 

3818 

4770.3 

18970 

310.5 

3438.7 

72.2 

7:30 

755.0 

3815 

4767.5 

18980 

311.0 

3446.0 

72.3 

8:30                  757.0           3863 

4826.4 

19020     |       311.7 

3461.1           71.6 

9:30                  756.0           3868           4830.2 

19120     i       315.2         3518.3           72.8 

10:30                  757.0           3873            4838.9 

19095           312.0         3478.1           72.1 

11:30                  756.5           3859 

4821.4 

19120 

312.8 

3491.6            72.4 

12:30  a.m.         757.0 

3870       j     4835.2 

19175 

315.7         3534.1            73.0 

1:30                  756.5 

3672       !     4587.8 

18790 

302.0     !     3315.0           72.5 

2:30                  757.0           3667 

4581.6 

18776 

300.0         3288.4     i       71.5 

3:30                  757.0     ;       3890 

4860.2 

19190           316.3         3543.5     j       72.8 

4:30                  757.5           3891 

4861.4 

19160     ;       315.6         3530.2           72.6 

5:30                  754.7           3861 

4823.9 

19110     !       317.1     !     3337.7 

73.2 

6:30                  757.0           3865           4828.9 

19005     i       314.8         3492.7           72.4 

7:30                  754.7           3706       :     4630.4 

18710     !       308.6         3370.8           73.0 

8:30                  745.6           3659 

4571.5 

18100           309.7     !     3272.5           71.5 

9:30                  745.6           3651 

4536.5 

17890 

308.9         3226.2           71.5 

10:30                  745.0           3619 

4521.6 

17795 

312.2         3243.4 

71.8 

11:30                  747.0           3618 

4519.1 

17806 

313.3         3256.8           71.8 

Average 

756.1 

• 

72.5 

Average  efficiency,  1st  period  of  8  hr.  =•  73 . 0  per  cent. 
Average  efficiency  2nd  period  of  8  hr.  -»  72 . 3  per  cent. 
Average  efficiency  3rd  period  of  8  hr.  —  72. 5  per  cent. 

No.  of  cycles  per  sec.  12:30  p.m.  to  6:30  a.m.  =•  25.5 
No.  of  cycles  per  sec.  6:30  a.m.  to  12:30  p.m.  —  25.0 


TABLE  3    TEST  OF  INDIVIDUAL  PUMPS 
SOUTH  STREET  STATION,  SEPTEMBER  3,  1908 


Time 

No.  of 

Gal.   per 

Pressure 

LB.  PER     SQ.  IN. 

h.p. 

Efficiency 

pump 

min. 

delivery 

Inj. 

Net 

output 

of  pump 

12:58-  1:14 

1 

3372 

344.4 

29.3 

315.1 

620 

74.6 

1:22-  1:37 

2 

3809 

336.0 

27.9 

308.1 

683 

70.1 

1:43-  1:58 

3 

3495 

334.0 

28.7 

305.3 

623 

73.2 

2:03-  2:18 

4 

3705 

334.5 

27.8 

306.7             662 

76.0 

2:24-  2:38 

6 

3740.7 

344.5 

28.8 

315.7             689 

77.0 

Immediately'following  the  24-hr,  test  for  capacity. 


456  HIGH-PRESSURE    FIRE-SERVICE    PUMPS 

65  Immediately  after  the  close  of  the  endurance  test  of  24  hours, 
a  short  test  was  run  on  each  motor  separately,  which  was  continued 
long  enough  after  uniform  results  were  shown  to  obtain  12  to  15 
readings.     This  test  was  run  for  the  purpose  of  ascertaining  whether 
there  were  deficiencies  in  any  of  the  individual  motors,  and  to  meet  the 
requirements  specified  in  the  printed  specifications  for  the  work,  viz: 
that  each  pump  should  be  free  from  defects,  should  have  a  capacity 
of  3,000  gal.  per  min.  and  an  efficiency  not  less  than  70  per  cent. 
The  results  of  these  tests,  Table  3,  show  that  the  individual  pumps 
had    an    efficiency    from    4   per  cent  to  6  per   cent  in  excess    of 
the  average  when  operated  together,  and  that  the  capacity  for  the 
specified  discharge  pressure  was  considerably  in  excess  of  the  require- 
ment of  the  specification.     It  is,  I  believe,  generally  the  case  that 
individual  centrifugal  pumps  delivering  water  into  a  main  singly 
show  a  greater  efficiency  by  from  4  per  cent  to  6  per  cent  than  the 
same  pumps  delivering  together  into  a  single  main,  due  probably  to 
less  loss  in  eddy  currents  and  friction  head,  etc. 

GANSEVOOET  STREET  STATION  TEST 

66  The  endurance  test  of  the  Gansevoort  Street  Station  with  all  the 
pumps  in  operation  was  begun  at  9:45  a.m.,  September  5,  after  the 
pumps  had  been  operated  for  about  20  min.  giving  uniform  results. 
The  test  was  continued  for  24  hr.  •  The  method  of  testing  and  the 
various  observers  were  the  same  as  for  the  tests  at  the  South  Street 
Station  and  the  results  are  given  in  Tables  4  to  6. 

67  For  the  Gansevoort  Street  Station  the  efficiency  average  for  24 
hr.  was  72.9  per  cent,  with  a  variation  (excepting  the  first  hour)  of  less 
than  one-half  of  1  per  cent.     It  fell  below  70  per  cent  during  the  first 
hour,  which  was  due  to  the  opening  of  an  automatic  relief  valve  on 
pump  No.  2,  which  discharged  some  of  the  water  into  the  suction 
before  it  had  been  metered.     For  that  reason  the  efficiency  during  the 
first  hour  has  not  been  considered  in  determining  the  performance 
of  the  pumps. 

68 1  The  least  capacity  during  the  eight  consecutive  hours  when 
all  the  water  pumped  passed  through  the  meters  occurs  from  10.45 
a.m.  to  6.45  p.m.  The  average  capacity  during  this  time  is  17,419 
gal.  The  average  net  pressure  in  pounds  is  324.3  which  is  nearly 
16  Ib.  in  excess  of  the  contract  requirements.  The  average  efficiency 
for  the  period  above  is  72.90  per  cent. 


HIGH-PRESSURE    FIRE-SERVICE    PUMPS 


457 


TABLE  4     HOURLY  AVERAGE    OF  READINGS   OF  DISCHARGE  AND  INJECTION 

GAGES  ON  PUMPS 
GANSEVOORT  STREET  PUMPINO  STATION,  SEPTEMBER  5  AND  6.  1908 


PUMP 
No   6 

PUMP  No.  4 

PUMP  No.  2    PUMP  No.  1    PUMP  No.  3      AVERAGE 

NET 

HOUR 

PRES- 

SURE 

LB. 

Disc. 

Inj. 

Disc. 

Inj. 

Disc. 

Inj. 

Disc. 

—  „.     Inj. 

Disc. 

Inj. 

9:45-10:30  342.4 

24.7!  342.6 

25.6 

344.8 

24.9 

346.9 

25.2  345.1   25.3   338.4   25.1 

319.3 

10:45-11:30  347.4 

24.7!  347.1 

25.7   345.4 

25.2 

348.4 

25.41  346.4  25.2   346.9   25.2 

321.7 

11:45-12:15 

348.9 

24.9i  348.9 

26.2!  347.9 

25.7 

349.4 

25.9   347.  9i  25.9  348.6   25.7 

322.9 

12:45-  1:15  351.425.7   350.9 

27.7J  350.1 

26.7 

352.4 

26.9 

350.4 

26.9  351.0  26.8 

324.2 

1:45-  2:15 

352.425.7   352.4 

27.4 

350.9 

26.7 

353.4 

26.7 

351.4 

26.9!  352.1 

26.7 

325.4 

2:45-  3:15 

352.925.7 

352.9 

27.7!  351.4 

26.9 

354.9 

27.2 

351.4 

27.2  352.7   26.9 

325.8 

3:45-  4:15 

353.926.4  353.9 

28.2 

353.4 

27.7 

355.4 

27.4 

353.4 

27.9 

354.0 

27.5 

326.5 

4:45-  5:15 

354.4 

26.91  354.4 

28.7   353.4 

27.9   355.9 

28.2   353.4 

28.7 

354.3 

28.1 

326.2 

5:45-  6:15 

349.  927.  4|  349.9 

29.7 

350.4 

28.7 

351.9 

28.9   350.9 

29.2 

350.6 

28.8 

321.8 

6:45-  7:15 

349.928.4  348.9 

30.2  349.4 

29.2 

351.4 

29.2   349.4 

29.4 

349.8 

29.3 

320.5 

7:45-  8:15 

351.928.9 

350.9 

30.7 

350.4 

29.7 

352.4 

29.2!  349.9 

29.9 

351.1 

29.7 

321.4 

8:45-  9:15 

351.929.7 

351.9 

30.  9i  350.6 

29.7 

353.4 

29.9!  350.9  30.7 

351.7 

30.2 

321.5 

9:45-10:15 

352.429.7 

354.4 

30.9!  351.4 

30.2 

353.4 

30.4 

352.9 

30.9 

352.9 

30.4 

322.5 

10:45-11:15 

354.4 

30.4 

353.9 

31.2|  353.4 

30.2 

354.9 

30.9 

353.4 

31.2 

354.0 

30.8 

323.2 

11:45-12:15 

354.431.2 

353. 

31.7 

352.9 

31.2 

353.9 

31.7 

352.9 

31.2 

353.5 

31.4 

322.1 

12:45-  1:15 

353.931.2 

352. 

31.7 

352.9 

31.2 

354.9 

31.7 

353.4 

31.2 

353.5 

31.4 

322.1 

1:45-  2:15 

352.4i31.2 

351. 

32.2 

352.9 

31.2 

354.4 

31.9 

353.4 

31.2 

353.0 

31.5 

321.5 

2:45-  3:15 

350.431.7 

349. 

32.  2J  349.4 

31.4 

351.9 

32.2 

350.4 

31.7 

350.3 

31.8 

318.5 

3:45-  4:15 

350.9132.2   350. 

32.7 

348.9 

31.2 

351.4 

32.7 

348.4 

31.4 

350.0 

32.0 

318.0 

4:45-  5:15 

350.9J31.9   350. 

32.4 

350.4 

31.2 

352.9 

32.2   349.9 

31.2 

350.9 

31.8 

319.1 

5:45-  6:15 

352.431.2|  351.9 

32.  2i  352.4 

30.7 

353.4 

31.  7|  351.9 

31.4 

352.4 

31.4 

321.0 

6:45-  7:15 

350.9 

29.9!  349.9 

31.2 

349.4 

29.9 

351.9 

30.7  349.4 

30.9 

350.  3j  30.5 

319.8 

7:45-  8:15 

349.4 

28.7  349.4 

29.7 

347.4 

29.4 

349.9 

29.2   347.9 

29.4 

348.8!  29.3 

319.5 

8:45-  9:45 

348.1 

27.4 

347.7 

28.9 

346.4 

28.0 

348.4 

28.0 

346.4 

28.5 

347.4 

28.2 

319.2 

Readings  corrected  for  error  of  gage  and  to  center  of  pumps. 

69  The  average  capacity  for  the  entire  test  is  17,867  gal.  which 
was  obtained  with  an  average  speed  of  753.6  r.p.m. 

70  Immediately  after  the  completion  of  the  endurance  test  of  24 
hours  duration,  each  pump  was  tested  when  operating  alone  for  a 
period  sufficiently  long  to  obtain  12  to  15  readings  after  they  had 
become  practically  uniform.     These  tests  gave  in  every  case  an 
efficiency  several  per  cent  greater  than  that  obtained  when  the  pumps 
were  all  discharging  into  the  same  main. 

CONCLUSIONS 

71  It  appears  from  the  endurance  test  in  each  station  that  the 
capacity,  efficiency  and  pressure  exceeded  the  contract  requirements 
by  a  large  margin,  and  that  during  the  endurance  test  no  mechanical 


458  HIGH-PRESSURE    FIRE-SERVICE    PUMPS 

TABLE  5     COMPUTATION  OF  PUMP  EFFICIENCIES 
GANSEVOORT  STREET  PUMPINO  STATION.  SEPTEMBER  5  AND  6,  1908 


Hour 
Beginning 

r.p.m. 

Total  kw. 
per  hr. 

Total  h.p. 
from 
motors 
(input) 

Gal.  per 
min. 

Net 
pressure 
Jb. 

h.p. 
delivered 

Efficiency 
per  cent 

9:  45  a.m. 

740 

3671 

4586.5 

17107 

319.3 

3188.9 

69.5 

10:45                  749 

3589 

4484.2            17310 

321.7 

3251.0 

72.5 

11:45                  750 

3591 

4486.7            17290 

322.9 

3259.3 

72.9 

12:45                  752 

3591 

4486.7            17280 

324.2 

3270.5 

72.9 

1:45  p.m.          752 

3604 

4502.9            17285 

325.4 

3283.6 

72.9 

2:45 

753 

3604 

4502.9     !        17315 

325.8 

3293.3 

73.3 

3:45 

753 

3630 

4535.3            17345 

326.5 

3306.1 

72.9 

4:45 

753 

3685 

4604.0 

17670 

326.2 

3365.0 

73.1 

5:45 

756 

3696 

4617.9 

17855 

321.8 

3354.4 

72.6 

6:45 

756 

3661 

4574.0 

17825 

320.5 

3335.2 

73.4 

7:45                  754 

3676 

4592.9            17775 

321.4 

3335.2 

73.3 

8:45                  753 

3685 

4604.0           17755 

321.5 

3332.5 

72.8 

9:45                  755 

3657 

4569.0 

17720 

322.5 

3336.2 

72.9 

10:45                  755 

3693 

4614.2 

17755 

323.2 

3350.1 

72.7 

11:45                  756 

3704 

4627.9 

17830 

322.1 

3352.8 

72.6 

12:45  a.m.          756 

3753 

4689.0 

18195 

322.1 

3421.4 

73.0 

1:45                 756 

3760 

4697.8 

18310 

321.5 

3436.6 

73.3 

2:45                  756 

3735 

4665.5 

18315 

318.5 

3405.5 

73.0 

3:45                  755 

3725 

4654.0 

18290 

318.0 

3395.5 

73.0 

4:45                  756 

3743 

4677.6 

18315 

319.1 

3411.9 

73.0 

5:45                  756 

3784 

4727.9            18330 

321.0 

3435.0 

72.7 

6:45                  755 

3747 

4681.6     |       18315 

319.8 

3419.4 

73.0 

7:45                  755 

3723 

4656.5 

18255 

319.5 

3405.0 

73.1 

8:45                  755 

3722 

4655.3 

18189 

319.2 

3389.5 

72.8 

Average               753  .  6 

72.9 

Average  efficiency,  1st  period  of  8  hr.  =  72 . 9  per  cent. 
Average  efficiency,  2d  period  of  8  hr.  —  73 . 0  per  cent. 
Average  efficiency,  3d  period  of  8  hr.  =  72 . 9  per  cent. 

No.  of  cycles  per  sec.  9:45  a.m.  to  2:45  p.m.  =«  25.00 

No.  of  cycles  per  sec.  2.45p.m.  to  4.45p.m.   =•  25.25 

No.  of  cycles  per  sec.  4:45  p.m.  to  6:45  p.m.  =  25.50 

No.  of  cycles  per  sec.  6:45  p.m.  to  7:45  p.m.  =  25.00 

No.  of  cycles  per  sec.  7:45  p.m.  to  9:45  p.m.  =  25.25 

No.  of  cycles  per  sec.  9:45  p.m.  to  9:45  a.m.   =  25.50 


or  electrical  defects  were  observed.  During  the  test  of  the  South 
Street  Station  one  of  the  pumps  was  stopped  for  half  an  hour  to 
repair  the  motor  insulation,  while  during  the  test  of  the  Gansevoort 
Street  Station  no  stop  was  made.  The  bearings  in  both  stations 
were  in  perfect  condition  at  the  end  of  the  test  and  the  temperature 
of  the  motors  not  sufficiently  high  to  interfere  with  the  continuous 
operation  for  a  longer  period.  Apparently  the  endurance  test  could 
have  been  continued  indefinitely  without  injuriously  overworking 
or  overloading  the  pumps  and  motors. 


HIGH-PRESSURE    FIRE-SERVICE    PUMPS 


459 


460 


HIGH-PRESSURE    FIRE-SERVICE  PUMPS 


72  The  specifications  call  for  pumping  sea  water,  which  most 
authorities  consider  to  be  approximately  2.5  per  cent  heavier  than 
fresh  water.  The  effect  of  substituting  sea  water  for  fresh  water 
would  have  been  to  reduce  the  capacity  of  the  pump  by  about  2J 
per  cent  for  the  same  horse-power  delivered  by  the  motor,  without 
sensibly  affecting  the  efficiency.  Because  of  the  large  capacity 


Scale  of  Efficiency  per  cent 

-6000- 
—5500- 
—5000- 
—4500- 
—4000- 
—3500- 

o/yv) 

Scale  of  Capacity-Gallons  per  Minute 

90 

^ 

X, 

^700 

80 

*  —  • 

x^. 

^Y 

NT 

"0 

/ 

5 

^ 

"^ 

' 

0 

6 

fiOO  -" 

fiO 

A 

A 

Sa 

s 

/ 

a 

500  o 

40 

// 

- 

\ 

'I 
4*tf) 

30 

V 

20 

' 

• 

10 

50 


450 


100         150         300         250         300         350         400 
Net  Pressure  on  Pump  Lb.  per  Sq.  In. 

FIG.  8    CHARACTERISTIC  CURVES  OP  THE  PUMP  FOR  VARYING 
DISCHARGE-PRESSURES 

RESULTS    OF    TESTS 

shown  by  the  pump,  this  does  not  materially  affect  the  results  in 
relation  to  the  contract  requirements. 

73  The  data  and  results  of  the  tests  at  the  two  stations  are  given 
concisely  in  the  tables.  The  efficiency  is  given  as  computed 
for  each  hour,  and  shows  a  slight  variation  which  probably  can  be 
accounted  for  by  changes  in  the  amount  of  water  leaking  past  the 
balancing  piston.  The  individual  pump  tests  at  the  South  Street 


HIGH-PRESSURE    FIRE-SERVICE    PUMPS 


461 


Station  show  a  variation  in  efficiency  from  70  per  cent  to  77  per  cent, 
and  at  the  Gansevoort  Street  Station  from  70  per  cent  to  79  per  cent. 
This  variation  may  have  been  due  to  the  structure  of  the  pumps  but  in 
my  opinion  is  more  probably  due  to  variable  leakage  past  the  bal- 
ancing piston  or  through  the  relief  valves. 

74  Pump  No.  6  at  the  Gansevoort  Street  Station  was  tested  with 
varying  openings  of  the  valve  in  the  discharge  pipe.  The  results  are 
shown  in  the  latter  half  of  Table  6. 

TABLE  6      TEST  OF  INDIVIDUAL  PUMPS 
GANSEVOORT  STREET  STATION,  SEPTEMBER  6,  1908 


Time 

No.  of 

pump 

Elect. 
h.p. 
input 

Gal.  per 
min.  Hg. 
Col. 

Pressure 
delivery 

LB.  PER  SQ.  IN. 

h.p. 
output 

Efficiency 
of  pump 

Inj. 

Net 

10:05-10:31 

1 

916 

3800 

356.8 

35.4 

321.4 

711 

77.6 

10:36-10:51 

2 

877 

3800 

350.8 

35.1 

315.7 

700 

70.8 

10:54-11:12 

3 

920.5 

3820 

350.4 

34.1         316.3 

703 

78.0 

11:17-11:30 

4 

892 

3751.4 

352.5 

35.6 

316.9 

695 

77.7 

11:37-11:53 

6             899 

3880 

350.9 

35.2         315.7 

714 

79.4 

11:55-12:03 

6             880.3 

3457 

376.1 

36.0 

340.1 

686 

77.9 

12:03-12:07 

6             929 

4500 

304.4 

34.6 

269.8 

708 

76.1 

12:09-12:13 

6             946 

5070 

255.6 

33.6 

222.0 

654 

69.4 

12:24-12:28 

6 

952 

5500 

207.4 

33.2 

174.2 

559 

58.7 

12:32-12:36 

6 

927 

5588 

155.2 

33.2 

122.0 

397 

42.8 

Immediately  following  the  24-hr,  test  for  capacity. 

PRACTICAL    RESULTS    FROM    THE    NEW    SYSTEM 

75  The  high-pressure  fire  system  in  New  York,  which  was  put 
officially  into  service  on  July  6,  1908,  has  been  successfully  operated 
at  many  fires,  but  it  had  a  crucial  test  on  January  7,  8  and  9,  1909, 
when  it  was  brought  into  service  for  five  simultaneous  fires,  three  of 
them  of  more  than  the  usual  extent  and  activity,  and  one  particu- 
larly so.     Information  upon  the  results  attained  with  the  system  and 
the  amount  of  water  consumed  was  given  by  Chief  Engineer  I.  M. 
de  Varona  and  published  in  the  Engineering  News  of  February  11, 
1909. 

76  The  fires  occurred  at  Hudson  and  Franklin  Streets,  Hester 
Street  and  the  Bowery,  Houston*  Street  and  Broadway,  Sixth  Ave- 
nue and  17th  Street,  and  Houston  Street  and  the  Bowery.     The 
situation  became  so  dangerous  that  every  engine  south  of  37th  Street, 
or  40  engines,  were  summoned,  as  well  as  a  force  consisting  of  12 
battalion  chiefs  and  more  than  600  men,  but  there  was  no  need  to 
use  a  single  one  of  the  engines. 


462 


DISCUSSION 


77  As  the  violence  of  the  fires  increased,  additional  pumps  were 
brought  into  service,  so  that  at  one  time  four  pumps  and  motors  were 
in  commission  at  the  South  Street  Station  and  three  pumps  at  the 

TABLE  7     SPECIFIED   CHEMICAL   ANALYSIS   FOR  PUMP  MATERIALS 


Nickel  steel 

Medium 
steel 

Steel 
forging 

Steel 
casting 

Parts  of  1  per  cent     ... 

Phosphorus  not  to  exceed.  .   . 

0.04 

0  10 

0  04 

0.05 

Sulphur  not  to  exceed  

0.04 

0.04 

0.05 

Tensile  strength  at  rupture,  pounds 
Tensile  strength  at  elastic  limit, 

100,000 
65000 

650,000 
32  500 

75,000 
38000 

65,000 
32000 

Per  cent  elongation  in  8  in 

2 

22 

Per  cent  elongation  in  2  in  
Contraction  of  area  per  cent  
Carbon  not  less  than  

22 
32 
20  parts  of  1% 

22 
32 

18 
24 

Nickel  percentage  

21  to  24 

Gansevoort  Street  Station,  delivering  35,500  gal.  per  min.  against 
an  average  pressure  of  225  Ib.  at  the  pumps  and  205  Ib.  at  the  hydrants. 
During  the  operation  of  the  pumps  14,095,000  gal.  were  pumped  as 
recorded  by  the  meters,  and  the  current  used  was  81,450  kw-hr., 
the  cost  of  which  was  $1222. 


DISCUSSION  AT  NEW  YORK 

PROF.  GEORGE  F.  SEVER.1  The  electrical  features  of  this  installa- 
tion are  of  much  interest  but  the  reasons  for  selecting  that  system 
which  is  now  in  operation  should  be  given.  In  the  discussion  of  this 
problem  both  alternating  and  direct-current  power  were  considered  for 
the  operation  of  the  motor-driven  pumps,  and  alternating-current 
power  was  decided  upon.  The  reasons  for  such  selection  I  have 
noted  herewith: 

a  Absolute  simplicity,  which  is  the  key-note  of  the  electrical 

end  of  this  power  installation. 
1  Professor  of  Electrical  Engineering,  Columbia  University. 

NOTE. — The  high-pressure  system  was  designed  by  I.  M.  de  Varona,  Chief 
Engineer  of  the  Department  of  Water  Supply,  Gas  and  Electricity  of  New  York. 
It  was  also  constructed  under  his  supervision.  The  construction  of  the  electrical 
machinery  was  supervised  by  Prof.  Geo.  F.  Sever  as  Consulting  Engineer.  The 
details  of  construction  were  in  charge  of  Thomas  J.  Gannon,  John  P.  Reynolds 
and  Henry  B.  Machen,  assistant  engineers  of  the  department.  The  machinery 
of  each  station  was  designed  and  erected  by  the  Allis-Chalmers  Co.  of  Milwaukee. 


HIGH-PRESSURE    FIRE-SERVICE    PUMPS  463 

6  Commutating   apparatus   and   brushes  are  entirely  absent- 

c  Induction  motors  provide  very  quick  starting  when  it  is 
necessary  to  operate  the  station  on  a  fire  signal. 

d  There  is  less  expense  for  copper  in  the  distribution  system 
to  insure  continuity  of  service. 

e  The  induction  motor  is  a  less  expensive  apparatus  than  the 
direct-current  motor. 

/  With  the  induction  motor  there  are  absolutely  no  exposed 
live  circuits  in  the  station,  as  there  might  be  with  a 
direct-current  apparatus.  The  final  decision  was  for 
3-phase  service  at  6600  volts  and  25  cycles.  It  was 
decided  that  it  would  not  be  desirable  to  establish  a 
power  house  to  be  operated  by  the  city  because  it  would 
be  a  municipal  plant. 

2  In  order  to  insure  continuity  of  service  there  is  brought  to  each 
pumping  station  an  independent  feeder  from  each  of  the  two  Water- 
side stations  of  the  New  York  Edison  Company.   There  is  also  brought 
to  each  pumping  station  an  independent  feeder  from  the  nearest  sub- 
station of  the  New  York  Edison  Company,  as  follows:  to  the  Ganse- 
voort  Street  station  two  feeders  from  the  Horatio  Street  sub-station, 
and  to  the  South  Street  station  two  feeders  from  the  Duane  Street 
station  of  the  company.     Hence  there  are  really  four  independent 
sources  of  power  supply  for  each  pumping  station,  assuring  practi- 
cally no  possibility  of  shutdown. 

3  The  contract  for  electric  power  for  the  Manhattan  stations  was 
let  to  the  New  York  Edison  Company.     This  contract  provides  for 
two  payments,  the  first  for  a  reservation  of  3250  kw.  capacity,  of  gen- 
erating, distributing  and  controlling  apparatus,  available  at  either 
pumping  station  at  an  instant's  notice,  or  practically  without  any 
notice  at  all.     Thus  four  pumps  can  be  thrown  on  with  absolutely  no 
notice  to  the  New  York  Edison  Company  that  they  are  to  be  used. 
For  that  reservation,  and  care  and  maintenance  of  the  whole  distribu- 
ting system,  the  city  pays  about  $63,000  per  year,  and  the  city  also 
p&ys  one  and  one-half  cents  per  kw-hr.  for  all  high-tension  power 
used  in  each  station. 

4  Another  stipulation  in  the    contract  may  be  of  interest  to 
engineers  as  it  provides  for  the  protection  of  the  city.     This  stipu- 
lation is  as  follows:    "If  the  contractor,  under  the  terms  of  this 
contract,  shall  fail  to  maintain  and  deliver  a  continuous  and  uninter- 
rupted supply  of  electric  power  when  required,  the  contractors  shall  and 
will  pay  to  the  city  the  sum  of  five  hundred  dollars  per  minute  for 


464  DISCUSSION 

each  minute's  interruption  or  delay  of  electric  power  supply  after 
the  power  has  been  interrupted  or  delayed  for  three  consecutive 
minutes. "  So,  if  they  cannot  deliver  power  after  an  interruption  of 
three  minutes,  immediately  a  charge  of  $500  per  min.  is  imposed  and 
is  deducted  from  the  bills  which  the  New  York  Edison  Company 
renders. 

5  The  operation  of  both  these  stations  is  extremely  simple.  The 
handle  of  the  oil  switch  is  turned,  throwing  the  6600  volts  directly  on 
the  stator  of  the  motor.  By  turning  a  hand  wheel,  the  motor  is 
brought  up  to  speed  in  less  than  33  sec.,  and  in  starting  the  current  is 
not  supposed  to  exceed  150  per  cent  of  the  full-load  current,  which 
is  64  amperes.  As  far  as  I  have  observed  the  operation  of  the  stations, 
there  has  been  absolutely  no  trouble  from  the  electrical  end,  no  trouble 
with  the  feeder  system,  and  none  with  the  motors,  and  I  think  the 
City  of  New  York  has  two  plants  which  will  give  it  for  many  years 
to  come  absolutely  no  trouble  whatsoever. 

WM.  M.  WHITE.  The  paper  deals  with  questions  in  which  I  am 
directly  interested.  The  methods  employed  in  making  the  tests 
were  probably  the  best  that  could  have  been  selected.  There  is 
probably  no  more  accurate  method  of  determining  the  quantity  of 
water  delivered  by  a  pump  than  by  the  venturi  meter,  especially 
when  in  the  hands  of  an  expert  who  is  familiar  with  its  workings. 
The  venturi  meter,  as  Professor  Carpenter  says,  has  been  used  for 
a  number  of  years;  it  has  been  tested  in  various  ways  and  proved  to 
give  accurate  results.  The  power  delivered  to  the  pumps  can  be 
most  carefully  measured  by  electrical  instruments. 

2  The  writer  accepts  without  question  the  various  efficiencies 
obtained  and  presented  by^the  author,  who  states,  calling  attention  to 
the  variation  in  efficiencies  obtained,  that  the  individual  observations 
do  not  agree  as  Jclosely  as  he  would  like.    I  do  not  think  Professor 
Carpenter  should  offer  any  apology  as  the  results  seem  to  agree  very 
closely,  and  certainly  are  as  accurate  as  are  generally  obtained  on  work 
of  this  kind.    The  efficiencies  obtained  on^ these  pumps,  though  not 
the  highest  that  have  been  obtained,  are  as  high  as  is  usual  for 
similar  conditions  of  head,  capacity  and  speed.    The  designers  of 
the  pumps  deserve  credit  for  the  performance  shown  by  the  pumps. 

3  I  am  at  a  loss  to  find  a  reason  for  the  variation  in  efficiencies  of 
the  pumps,  as  mentioned  in  Par.  65,  where  it  is  stated  that  individual 
pumps  delivering  water  into  a  main  singly  show  greater  efficiency 


HIGH-PRESSURE    FIRE-SERVICE    PUMPS  465 

than  the  same  pumps  delivering  together  into  a  single  main.  I 
assume,  of Jcourse,  that  the  variation  in  efficiency  refers  to^the  pumps 
when  they  are  delivering  exactly  the  same  quantity  against  the 
same  head  at  the  same  speed,  whether  working  singly  or  in  parallel. 
In  the  normal  operation  of  pumps,  it  would  be  a  fact  that  when 
one  pump  was  operating  from  a  suction  main  to  a  discharge  main, 
the  efficiency  of  that  pump  would  be  different  from  what  it  would 
be  when  working  with  another  pump  from  the  same  suction  main 
and  discharging  into  the  same  discharge  main,  because  the  two 
pumps  would  usually  be  working  against  a  higher  head  than  when  a 
pump  was  working  singly.  The  increased  head  on  the  pumps  would 
mean  a  decrease  of  capacity,  and  the  increase  of  power  demanded  by 
two  motors  instead  of  one  would  mean  a  slight  increase  in  line  loss, 
which  would  again  slightly  decrease  the  speed  and  slightly  change 
the  conditions  of  operation  for  two  pumps  over  that  which  would 
exist  when  one  pump  only  was  in  operation.  Of  course,  under 
thesejconditions,  the  two  pumps  would  show  different  efficiencies, 
because  the  efficiency  curve  of  a  pump  varies  as  its  capacity  and 
head. 

4  I  do  not  believe,  however,  that  this  is  the  condition  to  which 
Professor  Carpenter  refers.     I  assume  that  he  has  corrected  for 
this  difference,  and  has  obtained  from  two  pumps  working  in  parallel 
the  same  capacities,  heads  and  speeds  as  though  one  pump  were  in 
operation,  and  that  under  this  latter  condition  he  finds  the  differ- 
ence in  efficiency  in  the  two  pumps.    If  this  be  a  fact,  it  is  the  most 
important  point  brought  out  from  a  designer's  point  of  view. 

5  I  am  at  this  time  attempting  to  duplicate  the  conditions,  to  see 
whether  the  efficiencies  are  different  under  the  same  conditions  of 
capacity,  head  and  speed,  as  mentioned  by  Professor  Carpenter. 

GEORGE  L.  FOWLER.  A  number  of  years  ago  I  was  associated 
with  Joseph  Edwards,  who  at  that  time  had  the  contract  for  exca- 
vating the  ship  channel  in  New  York  Harbor,  probably  one  of  the 
first,  if  not  the  first,  very  large  hydraulic  engineering  projects  suc- 
cessfully accomplished  by  the  contractor  and  to  the  satisfaction  of 
the  Government. 

2  The  ship  channel  leading  from  the  Narrows  down  to  Sandy 
Hook  and  out  to  sea,  is  about  15  miles  long,  and  runs  almost  due 
south  first,  turning  to  nearly  due  east  before  reaching  Sandy  Hook, 
and  passing  through  Gedney  Channel  to  the  sea.  Cutting  across  it  is 


466 


DISCUSSION 


the  Swash  Channel,  not  used  by  any  deep-draft  boats.  When  the 
work  was  undertaken  New  York  Harbor  was  shoal  at  two  points  on 
the  Gedney  Channel  and  the  ship  channel,  where  the  water  depth 
was  a  little  less  than  24  ft.  The  Government  had  a  survey  made  and 
an  estimate  of  costs  based  on  material  actually  removed  by  the  ordi- 
nary methods  of  dredging.  Through  the  open  space  from  Sandy 
Hook  to  Coney  Island  the  whole  lower  bay  is  subject  to  all  the  winds 
coming  in  from  the  Atlantic  on  the  east  and  across  Raritan  Bay,  so 
that  the  water  is  nearly  always  rough.  Two  contractors  had  at- 
tempted the  work  by  ordinary  bucket  dredging  and  both  had  failed. 


FIG.  1    HYDRAULIC  DREDGER  FOR  DEEPENING  SHIP  CHANNELS 

3  In  the  ship  channel  the  material  was  sand  and  sedimentary 
clay,  lying  ove/hard^sand;  in  the  Gedney  Channel  it  was  gravel,  shell 
and  sand,  for  two  feet  overlying  hard  shingle.      Hydraulic  dredging 
was  specially  suited^for  this  kind^of  Vork,  and  many  kinds  of  material 
were  removed Jrom^the  channel  besides  the  ordinary  silt. 

4  Three  sea-going  vessels  were  built  for  this  work  by  the  Joseph 
Edwards  Company:  the  Reliance,  the  Advance,  and  the  Mt.  Waldo. 
Fig.  1  shows  the  general  arrangement  of  the  ships.     At  A  is  the  long 
drag  aft,  where  the  pipe  goes  into  the  vessel  and  where  the  pumps  are 
located,  each  driven  by  a  192-h.p.  engine  at  178  r.p.m.     The  suction 
and  delivery  pipes  were  15  in.  in  diameter,  with  a  shell  of  40  in.     The 


HIGH-PRESSURE    FIRE-SERVICE    PUMPS 


467 


pumps  delivered  10,000  gal.  per  min.  at  a  velocity  of  1100  ft.  The 
efficiency  was  thus  between  65  and  70  per  cent,  although  in  later 
tests  made  by  the  Government,  when  nothing  but  water  passed 
through  the  pipes,  the  efficiency  rose  to  as  high  as  80  per  cent. 

5  The  shoe  used  is  a  hook  that  drags  along  the  bottom,  chains 
being  fastened  to  the  vessel  for  this  purpose.  The  vessel  never 
stopped  from  morning  to  night,  simply  running  out  to  sea,  dumping, 
and  comingrback^again  tovwork. 


FIG.  2    DETAIL  OP  END  OF  SUCTION  LINE 

6  At  the  point  L,  Fig.  2,  was  the  heavy  shoe  that  served  to  dig 
into  the  mud  and  gravel.  At  0  was  a  butterfly  valve,  kept  open  all 
the  time  to  admit  water  above  the  drag  to  mix  with  the  material 
raised.  At  the  bottomTK  was  another  valve  which  could  be  opened 
in  an  emergency,  in  case  not  enough. water  was  admitted  afc  0.  . 


468 


DISCUSSION 


7  The  pump  itself  was  of  a  plain  centrifugal  type,  40  in.  in  diam- 
eter, with  vanes  cut  away  at  the  center,  as  shown  in  Fig.  3.  Because 
of  this  arrangement,  the  material  would  come  in  at  C  and  out  of  the 


FIG.  3    SECTIONAL  VIEW  OF  CENTRIFUGAL  PUMP  FOR  DREDGING 

vanes  at  the  discharge,  without  damaging  the  pump  when  heavy 
substances  were  drawn  in.     The  three  vanes  were  made  with  wings 


HIGH-PRESSURE    FIRE-SERVICE    PUMPS 


469 


bolted  on,  and  accessible  from  both  sides.  The  thrust  was  taken  up 
by  the  bearing  at  T  (Fig.  4) ,  the  nuts  marked  m  being  screwed  into  a  head 
carried  by  the  bars  0,  bringing  the  thrust  plates  at  the  point  i.  The 
reason  for  threading  the  nut  m  was  to  adjust  it  to  the  vanes  in  proper 
relative  position  to  the  sides  of  the  pump.  That  is  a  simple  construc- 
tion maintained  ever  since,  with  the  exception  that  ball  bearings  are 
now  used. 

8  Although  the  pumps  were  originally  intended  to  take  water  and 
other  loose  material,  such  as  sand  and  gravel,  they  proved  capable  of 
lifting  practically  anything  that  came  in  their  way.  The  three  fol- 
lowing specimens  are  interesting  as  showing  the  pumps'  lifting  power: 


FIG.  4    DETAIL  OF  THRUST  BEARING  OF  PUMP 

a  A  piece  of  shaft  weighing  70  Ib.  raised  and  passed  by  a  15-in. 
dredging  pump;  improvement  of  New  York  Harbor, 
Steamer  Reliance. 

6  A  piece  of  tree  root  raised  and  passed  by  a  12-in.  pump  from 
14  ft.  of  water  at  Miami,  Fla. ;  Florida  East  Coast  Railway 
Company  improvements. 

c  A  piece  of  pig  iron  measuring  11  \  in.  by  4f  in.  by  3J  in.  and 
weighing  35  Ib.  raised  and  passed  by  an  8-in.  special  cata- 
ract wrecking-pump  from  15  ft.  of  water  from  the  wreck 
of  a  canal  boat  sunk  at  Puas  Dock,  Yonkers,  N.  Y.;  by 
Baxter  Wrecking  Company,  New  York. 

9  For  hydraulic  dredging,  the  Government  pays  by  the  scow  load 
and  gets  what  is  excavated.  In  ordinary  hydraulic  dredging,  like 
that  in  the  ship  channel,  about  15  per  cent  of  the  pump  discharge  was 
solid  matter.  About  40  per  cent  in  excess  of  the  amount  deposited 


470  DISCUSSION 

in  the  bins  went  overboard  with  the  overflow,  and  was  carried  out  to 
the  flats  at  the  sides  by  the  cross  currents,  which  also  carried  the  loose 
material  stirred  up  by  the  drag.  The  result  was  that  the  Government 
obtained  an  excavation  about  70  per  cent  in  excess  of  what  would 
have  been  obtained  had  all  of  the  material  removed  from  the  bottom 
been  caught  in  the  bins.  This,  of  course,  greatly  reduced  the  actual 
cost  of  the  excavation.  For  example :  the  last  contract  made  on  the 
ship  channel  was  at  the  rate  of  16  J  cents  per  yard,  while  with  the 
allowance  indicated,  above  the  actual  cost  per  yard — channel  meas- 
urement— it  was  about  11  cents. 

10  As  for  the  time  of  loading,  some  records  indicate  that  this 
ship,  157  ft.  long  and  with  a  capacity  of  650  cu.  yd.,  was  loaded  in 
48  min.;  there  are  also  records  of  its  being  loaded  at  the  rate  of  16  cu. 
yd.  per  min.,  of  solid  matter  placed  in  the  bins;  and  records  of  its 
taking  out  to  sea  nearly  4000  cu.  yd.  per  day.  The  vessel  was 
worked  in  all  kinds  of  weather,  even  when  tackles  had  to  be  used  to 
board  her;  and  yet  the  ship  was  taking  her  load  steadily.  Except 
in  the  case  of  an  actual  breakdown  the  work  could  be  carried  on  for 
16  hr.  per  day. 

JOHN  H.  NORMS.  In  a  pumping  plant  of  the  character  described, 
this  type  of  equipment  seems  in  the  present  state  of  the  art  the  most 
suitable  that  could  have  been  selected.  I  would  like,  in  this  connec- 
tion, to  call  attention  to  another  type  of  installation  for  service  of 
this  kind,  though  not  on  so  large  a  scale,  which  appeals  to  me  as 
being  more  desirable  than  the  electric-driven  centrifugal  pumping 
plant  taking  its  power  from  a  public  utilities  company. 

2  At  Coney  Island  was  installed  the  first  plant  operated  by  the 
City  of  New  York  for  fire  protection  by  means  of  water  delivered 
into  mains  under  high  pressure,  with  the  idea  of  taking  care  of  a 
restricted  area  where  there  was  great  danger  from  fire. 

3  This  plant  consists  of  three  150-h.p.  three-cylinder,  vertical 
gas  engines  direct-connected  to  triplex  pumps,  each  unit  capable  of 
pumping  1500  gal.  per  min.  against  a  pressure  of  150  Ib.     These 
engines  take  their  fuel  from  the  mains  of  the  local  gas  company  and 
can  be  arranged  if  necessary  to  run  on  gasolene.     They  are  installed 
in  a  building  on  city  property  and  are  arranged  to  take  their  water 
supply  from  the  city  mains  or  from  Coney  Island  Creek,  within  50  ft. 
of  the  pumping  station.     The  engines  are  started  with  compressed  air, 
and  the  three  units  can  be  started  up  in  less  than  three  minutes. 
On  every  occasion  they  have  been  found  ready  for  service  whenever 


HIGH-PRESSURE   FIRE-SERVICE   PUMPS  471 

the  demand  was  made  upon  them.     The  cost  of  this  pumping  station 
was  as  follows: 

Building $10,000 

Equipment 37,000 

$47,000 
The  annual  operating  expenses  are: 

Labor $13,140.00 

Supplies  and  Repairs 897 . 27 

Fuel 150.00 

$14,187.27 

4  By  comparing  the  foregoing  figures  it  will  be  evident  that  for 
service  smaller  than  is  required  in  the  City  of  New  York,  the  gas- 
engine-operated  triplex  pump  gives  an  economical  equipment  that 
can  be  allowed  to  stand  idle  for  any  length  of  time  and  yet  be  ready 
for  instant  service. 

5  New  York  City  pays  the  New  York  Edison  Company  an  annual 
charge  of  $90,000  for  the  privilege  of  calling  for  sufficient  current  to 
operate  the  equipment  at  any  time.     This  item  capitalized  at  5  per 
cent  would  pay  for  a  good-sized  gas-engine  plant. 

6  The  following  data  were  taken  from  the  capacity  tests  of  the 
Coney  Island  units: 

Duration  of  test    '. 14      hr. 

Average  piston  speed  of  pump 90. 3  ft.  per.  min. 

Total  head  pumped  against 156 . 5  Ib. 

Average  pump  horsepower  for  each  unit 142.2  h.p. 

Average  gas  consumed  per  hour  for  the  3  units 8914.0  ft. 

Average  capacity 4512 . 0  gal.  per  min. 

Slip  of  pump 3 . 45  per  cent 

Average  efficiency  of  pumps 82 . 00  per  cent 

J.  R.  BIBBINS.  Although  Professor  Carpenter's  paper  deals  pri- 
marily with  multistage  pumps,  I  wish  to  direct  attention  to  the  ques- 
tion of  motive  power,  upon  which  the  success  or  failure  of  the  system 
practically  depends.  We  have  seen  excellent  examples  of  two  systems 
diametrically  opposed  in  regard  to  power  supply — the  electrical  and 
the  gas-driven  system.  Under  certain  conditions,  both  are  extremely 
serviceable.  The  first  high-pressure  installation  on  a  large  scale,  in 
this  country,  was  the  gas-driven  system  at  Philadelphia.  Although 
I  have  not  had  an  opportunity  to  follow  the  results  of  that  station  for 
the  past  two  or  three  years,  the  results  obtained  and  published  for 


472  DISCUSSION 

the  first  year  or  so  showed  that  such  a  system  of  gas-driven  pumps 
merits  every  consideration. 

2  First  as  to  the  security  of  power  supply:    In  Philadelphia  the 
Delaware  Avenue  station  receives  its  gas  supply  directly  from  a 
24-in.  trunk  main  running  between  two  very  large  gas  holders,  located 
in  different  parts  of  the  city.     Roughly,  the  pipe  line  measures  four 
miles  in  length,  its  capacity  constituting  a  considerable  reserve  in 
itself,  if  both  the  holders  were  unavailable.     There  is  no  intermedi- 
ary apparatus  whatever  between  the  pipe  line  and  the  engine ;  that  is, 
the  plant  may  draw  directly  on  these  two  large  holders  of  several 
million  cubic  feet  capacity.     This  constitutes  a  very  safe  and  reliable 
source  of  motive  power  which  can  hardly  be  paralleled  except,  per- 
haps, by  the  situation  in  the  New  York  electric  service,  where  there 
are  so  many  stations  to  draw  from. 

3  In  this  connection,  I  would  like  to  ask  whether  it  is  at  present 
possible  to  utilize  the  storage  battery  capacity  in  the  various  sub- 
stations for  reserve  service  at  the  high-pressure  pumping  station. 
It  is  stated  that  the  storage  batteries  are  available  for  reserve  in 
emergencies,  such  as  discontinuance  of  the  main  high-tension  current 
supply.     I  am  under  the  impression  that  an  inverted  rotary  requires 
a  direct-driven  exciter  to  maintain  a  definite  frequency  and  prevent 
racing.     Without  special  controlling  apparatus,  this  inversion  would 
be  impossible  in  the  ordinary  sub-station  equipment.     Possibly  special 
provision  has  been  made  in  the  New  York  systems,  in  which  case, 
the  security  of  power  supply  is  certainly  beyond  criticism.     In  other 
words,  would  it  be  possible  to  invert  the  synchronous  converters  on 
short  notice? 

4  Second,  quick  starting:    It  seems  to  be  a  fact  that  a  large  part 
of  the  minimum  time  required  for  the  starting  of  a  fire-service  station 
is  consumed  in  the  operation  of  the  motor-driven  by-pass  valves.     In 
Philadelphia  these  valves  are  operated  from  an  independent  supply, 
as  in  New  York,  and  at  least  fifteen  seconds  are  required  to  close  them ; 
whereas  the  engines  are  brought  up  to  speed  within  half  a  minute 
from  the  time  the  signal  is  given,  the  remaining  time  being  usually 
consumed  in  closing  this  motor-driven  valve. 

5  The  various  tests  of  the  Philadelphia  plant  showed  that  each  of 
the  units  could  be  readily  put  on  the  line  in  well  under  one  minute. 
It  is  an  interesting  fact  that  the  original  underwriters*  tests  specified 
the  time  limit  as  twelve  minutes  for  the  starting  of  the  first  three  units, 
whereas  the  whole  station  can  be  started  in  that  time,  and  has  been 
started  in  seven  minutes. 


HIGH-PRESSURE   FIRE-SERVICE   PUMPS  473 

6  During  the  36  days  of  preliminary  service  trials  of  the  Phila- 
delphia station,  out  of  one  hundred  alarms  given,  only  four  misses  were 
made  in  getting  any  of  the  eleven  units  started.     In  not  a  single 
instance  has  the  station,  as  a  whole,  failed  to  respond  to  the  service,  at 
least  during  the  period  over  which  my  observation  extended.     This 
has  been  accomplished  with  the  regular  operating  force  of  three  men. 

7  Third,  in  regard  to  the  cost  of  service  at  Philadelphia;     The 
only  data  on  a  large  fire  available,  are  those  of  the  fire  in  the  Coates 
Publishing  House,  which  lasted  about  nineteen  hours.     The  average 
cost  for  pumping  was  about  six  cents  per  thousand  gallons,  including 
gas,  wages  and  supplies.     The  cost  of  the  large  East  Side  service, 
cited  in  the  paper,  is  about  nine  cents  for  power  alone,  and  I  think 
this  does  not  include  the  readiness-to-serve  factor.     On  the  other 
hand,  it  is  patent  that  the  cost  of  service  in  either  the  gas  or  the 
electrical  station  is  relatively  unimportant.     The  main  desideratum 
is  reliability. 

8  Finally,  I  desire  to  advance  an  argument  for  the  development  of 
a  new  type  of  pump  unit,  namely,  a  high-speed  gas-driven  centrifugal 
pump.     Some  time  ago,  in  connection  with  water- works  service,  I 
found  great  difficulty,  even  with  the  present  high-speed  single-acting 
gas  engine,  in  matching  engine  speeds  with  those  required  in  centrifugal 
pump  work      However,  for  the  pressure  necessary  in  water-works 
practice,  about  125  lb.,  one  or  two  sizes  of  engines  were  found  to  be 
directly  applicable  to  multistage  pumps,  with  fair  proportion  of  parts 
and  good  efficiencies.     It  seems  possible  to  adopt  a  modified  type 
of  gas  engine  which  would  permit  the  direct  connection  mentioned. 

9  This  modification  would  naturally  follow  along  lines  of  short 
stroke  and  high  piston  speeds  with  perhaps  four  cylinders.     The 
engines  at  Philadelphia  were  designed  with  a  piston  speed  of  but  730 
ft.  per  min.  with  a  22-in.  stroke.     This  might  be  increased  to  1000  ft. 
per  min.  without  exceeding  present-day  limits,  especially  for  units 
designed  for  occasional  service.     Such  a  unit  would  find  immediate 
application  in  many  industries  and  would  combine  the  high  economy 
of  the  gas  engine  with  the  simplicity  of  the  centrifugal  pump.     The' 
efficiencies  shown  by  Professor  Carpenter  place  the  centrifugal  pump 
in  a  position  of  closest  competition  with  reciprocating  pumping  units. 

J.  J .  BROWN.  I  recently  made  a  series  of  tests  on  three  6-in. ,  8-stage 
centrifugal  pumps,  each  designed  for  1000  gal.  per  min.  and  560  lb. 
pressure  at  1200  r.p.m.  One  of  these  pumps  gave  an  efficiency  from 
wire  to  water  of  71  per  cent,  or  a  pump  efficiency  of  76  per  cent. 


474  DISCUSSION 

regret  that  Professor  Carpenter  did  not  give  the  results  of  his  tests 
on  the  New  York  fire-service  pumps  at  lower  capacities.  All  of  the 
tests  were  made  at  capacities  considerably  in  excess  of  that  for  which 
the  pumps  were  designed  and  they  apparently  show  their  best  effi- 
ciency at  approximately  25  per  cent  over  the  normal  rating.  This 
increased  efficiency  at  excess  capacity  seems  to  be  apparent  in  several 
recent  tests  made  on  high-lift  centrifugal  pumps.  The  8-stage 
machines  previously  referred  to  give  their  best  efficiency  at  1300  gal., 
or  about  30  per  cent  over  rating. 

2  Mr.  White  has  raised  a  question  as  to  the  difference  in  efficiency 
between  the  New  York  fire-service  pumps  working  in  multiple  and 
as  separate  units.     I  think  this  is  occasioned  by  the  variation  in 
capacity  of  the  pumps  when  working  together  on  a  common  suction 
and  discharge  line.     I  have  found  it  rather  difficult  to  balance  two 
centrifugal  pumps  on  a  common  discharge,  and  pitot  tube  tests  indi- 
cate in  almost  every  case  a  considerable  difference  between  the  amounts 
of  water  handled  by  the  individual  units  under  these  conditions. 

3  I  have  in  mind  one  installation  on  fire  service,  where  the  pumps 
were  called  upon  to  deliver  against  the  maximum  pressure  for  which 
they  were  designed  and  it  was  only  with  considerable  difficulty  that 
we  were  able  to  cut  in  additional  units.     I  think  that  if  venturi  meters 
or  pitot  tubes  had  been  placed  on  the  discharge  of  each  of  the  five 
pumps  when  they  were  working  in  multiple,  a  difference  in  capacity 
of  the  several  units  would  have  been  shown,  which  would  account 
for  the  difference  in  efficiency  observed  when  the  pumps  were  working 
individually  and  not  in  multiple. 

GEORGE  A.  ORROK.  At  the  time  of  the  award  of  contract  for  these 
fire  pumps,  the  New  York  Edison  Company  was  obtaining  proposals 
for  centrifugal  feed  pumps — a  somewhat  similar  service — and  eight 
1000-gal.  300-lb.  pressure  five-stage  pumps  were  purchased.  There 
was  no  attempt  to  obtain  a  high  guarantee  for  efficiency,  but  the 
builders  did  state  that  under  the  above  conditions  an  efficiency  of 
65  to  68  per  cent  would  be  obtained.  These  pumps  were  of  the  Jager 
type  and  under  test  showed  an  efficiency  of  about  68  per  cent. 

2  Fig.  5  shows  that  the  high-pressure  fire-service  pumps  are  of  the 
Kugel-Gelpke  type  and  should  be  a  trifle  more  efficient  because  of 
smaller  friction  and  leakage.  Seventy-one  per  cent  seemed  a  very 
high  efficiency  and  many  doubts  were  expressed  regarding  the  ful- 
fillment of  the  guarantees.  The  extreme  figure  of  79  per  cent 
obtained  is  probably  the  result  of  careful  design  and  extra  good  shop 


HIGH-PRESSURE    FIRE-SERVICE    PUMPS  475 

work  and  I  believe  has  not  been  excelled.  That  this  figure  came  as 
a  surprise  may  be  explained  by  the  fact  that  most  centrifugal  pumps 
are  stock  pumps  and  not  specially  designed  for  the  work  they  have  to 
do.  Pump  manufacturers  have  been  more  concerned  in  getting  a 
line  of  patterns  that  will  suit  standard  conditions  than  in  developing 
a  line  of  pumps  and  system  of  patterns  capable  of  doing  the  best  work. 
3  As  a  centrifugal  pump  is  a  mixed-flow  or  Francis  reaction  turbine 
reversed,  similar  care  in  design  and  construction  would  probably 
give  efficiencies  similar  to  those  of  the  best  makes  of  reaction  turbines, 
which  approximate  90  per  cent. 

FREDERICK  RAY.  The  difference  in  efficiency  of  the  units  oper- 
ated individually  from  that  obtained  when  several  were  operate  d  in 
parallel  might  be  due  to  the  different  rates  of  flow  through  the 
venturi  rneters  under  the  two  conditions.  With  one  pump  operating, 
this  flow  would  be  low  and  the  mercury  column  reading  would  be  but 
slightly  over  an  inch,  so  that  with  a  given  error  of  observation  the  per- 
centage of  error  would  be  much  greater  than  with  two  or  three  pumps 
discharging  through  the  same  meter. 

2  Professor  Carpenter  here  replying  that  the  pipe  connecting  the 
two  meters  was  open  all  the  time,  Mr.  Ray  continued: 

3  This  would  equalize  the  flow  in  the  meters,  so  that  the  mercury 
column   reading  when    the    whole   station   was  running  would   be 
about  6J  times  the  reading  with  one  pump.     It  has  not  been  my 
experience  that  parallel  operation  of  a  number  of  pumps  has  any 
tendency  to  decrease  or  otherwise  change  the  efficiency  obtained 
when  operated  individually.     The  efficiency  should  be  the  same,  and 
in  this  case,  as  the  pressures  were  taken  at  each  pump,  any  losses  in 
the  piping  system  due  to  parallel  operation  would  be  external  to  the 
gages  and  would  not  show  in  the  calculations.     If  the  pressure  had 
been  taken  at  the  discharge  of  the  whole  system,  losses  in  the  piping 
would  affect  the  results. 

4  Many   pumps  are  running  under  similar  conditions,  at  the 
efficiencies   given.      I  have  myself  obtained  efficiencies  of    80  per 
cent  and  higher,  but  I  do  not  rely  as  much  on  them  as  on  some  a 
little  lower.      I  am  now  testing  a  6-in.,  2-stage  underwriter  pump, 
having  a  normal  capacity  of  500  gal.  per  miri.  against  100  Ib.  pres- 
sure, which  has  developed  a  maximum  efficiency  of  73  per  cent. 

5  I  think  the  centrifugal  pump  is  the  ideal  one  for  fire  service, 
not  only  on  account  of  its  simplicity  and  reliability,  but   also  on 
account  of  its  characteristic  increase  in  capacity  as  the  pressure  is 


476  DISCUSSION 

reduced.  Thus,  the  500-gal.  underwriter  pump  referred  to  will  dis- 
charge 870  gal.  per  min.  at  60  lb.,  or  enough  for  four  streams  at  this 
pressure.  It  will  give  three  streams  at  90  lb.,  two  streams  at  110 
Ib.  and  one  at  117  lb. — all  at  constant  speed  without  any  regulation 
whatever. 

6  The  City  of  Toronto  has  recently  issued  specifications  for  cen- 
trifugal pumps  for  their  general  municipal  water  supply,  among  which 
are  several  fire  pumps  capable  of  discharging  against  300  lb.  pressure. 
These  pumps,  however,  are  to  be  equipped  with  variable-speed  induc- 
tion motors,  the  pressure  regulation  being  obtained  by  speed  variation. 
This  is  superior  to  throttling  regulation  from  the  standpoint  of  cur- 
rent economy  and  in  the  case  of  the  New  York  installation  a  con- 
siderable saving  could  be  made  by  this  means,  as  most  of  the  fires  can 
be  handled  with  200  lb.  pressure  or  less. 

H.  Y.  HA.DEN.  A  somewhat  unusual  result  obtained  from  this 
type  of  pump  is  that  as  the  total  head  continues  to  increase  beyond  a 
certain  point,  the  capacity  falls  off,  with  the  result  that  the  capacity 
curve,  as  given  in  Fig.  8,  shows  a  backward  tendency.  It  will  be 
interesting  to  get  the  explanation  of  this. 

2  There  is  unquestionably  a  large  field  in  fire  protection  for  steam- 
turbine-driven  centrifugal  pumps,  and  it  is  to  be  hoped  that  the  Fire 
Underwriters  will  officially  accept  this  type  of  fire  protection  unit. 
I  believe  that  a  properly  designed  centrifugal  pump,  for  high  speeds  and 
of  few  stages,  can  be  used  to  great  advantage  when  direct-connected 
to  high-speed  turbines. 

THOMAS  J.  GANNON.*  It  was  decided  to  use  electricity  as  power 
for  the  pumping  stations,  because  [the  first  cost  of  installation, 
yearly  cost  of  operation  and  maintenance  and  [fixed  charges 
were  estimated  to  be  lower,  taking  into  account  the  intermittent 
service.  The  construction  and  operation  of  a  steam  plant  were 
entirely  out  of  consideration  and  the  choice  lay  between  gas-engine- 
driven  and  electric-driven  pumps  receiving  power  from  outside 
sources. 

2  It  was  estimated  that  gas  operation  of  plants  equal  in  capacity 
to  the  present  electrically  driven  plants,  would  involve  a  fixed 
charge  of  $50,000  a  year,  in  addition  to  the  cost  of  the  gas  actually 
consumed.  The  question  as  to  who  should  build  and  maintain 

1  Engineer,  Dept.  Water  Supply,  Electricity  and  Gas,  Manhattan  Borough 
New  York. 


HIGH-PRESSURE    FIRE-SERVICE    PUMPS  477 

the  necessary  large  gas  mains,  the  cost  of  which  would  approximate 
a  million  dollars,  was  not  definitely  settled.  That  the  cost  of  a 
gas-engine-driven  pumping  plant  would  have  been  approximately 
double,  both  for  machinery,  building  and  area  of  land  to  be  pur- 
chased, is  borne  out  by  the  actual  costs  of  the  installations  in  Man- 
hattan and  at  Coney  Island. 

3  The  capacity  of  the  gas-operated  Coney  Island  plant  is  4500 
gal.  of  water  per  min.  against  a  head  of  150  Ib.  per  sq.  in.     The  com- 
bined capacity  of  the  two  pumping  plants  in  the  Borough  of  Man- 
hattan, as  originally  laid  out,  was  30,000  gal.  per  min.  against  a  head 
of  300  Ib.,  with  provision  in  each  station  for  three  additional  pumping 
units  of  a  capacity  of  3000  gal.  each,  making  a  total  combined  capacity 
of  48,000  gal.  per  min.  against  300  Ib.  pressure.     On  actual  test, 
however,  the  capacity  of  the  pumps  was  approximately  20  per  cent 
greater  than  the  designed  capacity. 

4  Furthermore,  the  flexibility  of  this  type  of  pump  permits  of  an 
increased  discharge  at  lower  pressures,  which  gives  a  capacity  of 
approximately  5500  to  5600  gal.  per  min.  for  pressures  between  150 
and  200  Ib.,  or  a  combined  total  capacity  of  55,000  gal.  per  min. 
against  200  Ib.  pressure.     This  corresponds  to  the  pressure  at  which 
the  station  is  operated  for  most  fires.     In  other  words,  the  water 
horsepower  of  the  electric-driven  as  compared  with  the  gas-engine- 
driven  plant  is  approximately  in  the  ratio  of  20  to  1. 

5  The  cost  of  the  machinery  in  the  Coney  Island  plant  was 
approximately  $37,000,  and  the  cost  of  the  building  approximately 
$10,000.     The  cost  of  each  of  the  two  Manhattan  pumping  stations 
complete,  exclusive  of  land,  was  practically  $240,000.    The  first  cost 
of  installation  of  the  gas-engine-driven  plant  is  therefore  more  than 
double  the  first  cost  of  installation  of  an  equivalent  electrically-driven 
plant,  in  the  city  of  New  York. 

6  The   high-pressure   fire-service   pumping   stations  went   into 
official  operation  on  July  6,  1908.     It  was  at  first  decided  to  put  the 
stations  in  service  only  when  called  on  by  the  fire  department,  and 
up  to  and  including  November  20,  1908,  the  pumping  stations  were 
called  upon  to  go  into  actual  service  for  but  17  fires.     On  that  date, 
the  method  of  operation  was  amended  so  that  the  pumping  stations 
are  put  in  service  in  response  to  every  alarm  in  the  high-pressure 
district,  and  continue  in  operation  awaiting  instructions  from  the 
fire  department.     Under  this  system,  from  November  20  to  December 
31,  1908,  the  pumps  responded  to  116  first  alarms.     From  the  best 
available  information,  water  was  used  in  55  instances,  making  a 


478  DISCUSSION 

total  of  72  fires  for  which  the  high-pressure  service  had  been  used 
up  to  that  date. 

7  To  insure  readiness  for  service  at  all  times,  daily  tests  are  made, 
of  at  least  half  an  hour's  duration,  unless  the  station  has  been  in 
actual  operation  during  the  preceding  24  hours. 

8  During  the  first  quarter  of  1909  the  number  of  alarms  received 
was  239,  and  water  was  taken  from  the  station  for  125  actual  fires. 
The  total  amount  of  water  pumped  was  17,840,000  gal.,  and  145,900 
kw-hr.  was  consumed.     It  was  on  January  7, 8  and  9  of  this  quarter 
that  the  three  large  simultaneous  fires  mentioned  in  Par.  75,  occurred, 
for  which  over  14,000,000  gal.  of  water  was  pumped,  leaving  about 
3,800,000  gaL  for  the  balance  of  actual  fires  occurring  during  the 
quarter.     For  these  three  simultaneous  fires  more  than  81,000  kw- 
hr.  was  consumed  while  the  total  consumption  of  power  for  the 
quarter  for  all  fires  and  testing  purposes  was  but  145,900  kw-hr. 

9  As  to  why  a  pump  running  singly  develops  a  higher  efficiency 
than  when  running  in  conjunction  with  several  others,  it  is  observed 
that  pumps  of  the  same  type  do  not  necessarily  develop  their  best 
efficiency  at  the  same  speed  and    pressure.     The  pump  running 
singly  will   naturally  develop  a  pressure  which  corresponds  to  its 
own  design,  but  when  working  in  multiple,  it  will  have  to  adjust 
itself  to  the  common  pressure. 

10  As  to  reliability  I  have  neither  seen  nor  heard  of  any  time 
when  any  one  of  the  ten  pumps  installed  in  the  Borough  of  Man- 
hattan has  failed  to  respond  instantly  when  called  on  for  service 
and  to  develop  the  full  pressure  on  the  system  within  one  minute's 
time.     At  no  time  in  service  have  the  pumps  shut  down  of  their 
own  accord. 

HENRY  B.  MACHEN.1  Among  the  many  difficulties  encountered 
during  the  construction  of  the  distribution  system,  perhaps  the 
greatest  was  that  due  to  the  congested  sub-surface  of  the  street, 
which  was  a  source  of  continual  extra  expense  to  the  contractor, 
and  of  worry  to  the  man  in  charge  of  selecting  the  location  for  the 
excavation  of  the  trench. 

2  The  intersection  of  Sixth  Avenue  and  Fourteenth  Street  may 
be  cited  as  an  example,  since  complete  notes  are  available,  due  to  the 
station  excavation  for  the  Hudson  Tunnels.  Here  there  were  nine 
gas  mains  east  and  west,  and  nine  north  and  south,  belonging  to 

1  Engineer,  Dept.  Water  Supply,  Electricity  and  Gas,  Manhattan  Borough, 
New  York. 


HIGH-PRESSURE    FIRE-SERVICE    PUMPS  479 

four  different  companies;  two  water  mains  in  each  direction;  sewers 
and  their  connections  on  each  side  of  the  street;  five  Edison  duct 
lines,  and  five  duct  lines  with  large  manholes  belonging  to  the  Con- 
solidated Telegraph  and  Electric  Subway  Company  or  the  Empire  City 
Subway  Company;  the  conduits  and  banks  of  ducts  of  the  Fourteenth 
Street  and  the  Sixth  Avenue  trolleys;  and  lastly,  the  columns  of 
the  elevated  railroad  with  their  deep  foundations. 

3  Through  this  network  the  high-pressure  main  had  to  be  so 
laid  that  the  construction  of  the  Sixth  Avenue  tunnel  would  not 
require  it  to  be  relaid.     The  excavation  was  carried  on  by  tunneling, 
with  here  and  there  an  opening  through  which  the  earth  could  be 
hoisted,  using  a  pail  let  down  by  a  rope.     The  pipe  was  lowered 
into  the  trench  some  distance  up  the  street  and  pulled  through, 
piece  by  piece,  inspection  of  the  running  of  the  joint  and  caulking 
being  almost  impossible,  since  the  space  admitted  but  one  man 
at  a  time  after  the  pipe  had  been  hauled  in. 

4  This  condition  existed  at  nearly  all  intersections  of  the  main 
thoroughfares,    such   as   Broadway,    Sixth   Avenue,  Fifth   Avenue, 
the  Bowery,  etc.,  and  accounts  for  the  high  cost  of  laying  the  mains, 
averaging  about  $11  per  ft.  complete. 

5  The  second  great  difficulty  encountered  was  in  obtaining  the 
prescribed  test,  which  called  for  450  Ib.  pressure  per  sq.  in.  to  be 
held  for  10  min.,  during  which  time  the  leakage  was  measured. 

6  The   system   contained  about   40,000  castings,    30,000   being 
straight  pipe,  tested  at  the  foundry  to  650  Ib.     The  specials  were  not 
tested.    All  these  castings,  as  already  stated,  were  tested  in  the 
ground  to  450  Ib.,  the  mains  being  under  pressure  in  sections  about  one 
block  long,  between  gates. 

7  During  the  eighteen  months  the  system  has  been^in  service, 
there  have  been  but  three  breaks  in  the  mains,  all  three*  in  castings 
which  had  been  subjected  to  the  foundry  test  of  650  Ib.,  two  breaking 
at  150  Ib.  and  the  third  at  300  Ib.  pressure. 

8  To  overcome  the  danger  should  a  break  occur  [during  a  fire, 
the  proposed  extensions] to  the  distribution  system  now  under  contract, 
amounting  to  about  $1,500,000,  are  laid  out  on  what  the  department 
calls  the  [duplex  system.     This  method  of  overcoming  the  difficulty 
was  first  suggested  by  Mr.  Blatt,  assistant  engineer  of  the  high- 
pressure  bureau.     It  consists  of  laying  two    entirely  independent 
systems  of  mains^and  hydrants  in  alternate  streets,  the  hydrants 
of  one  system  being  painted  red  and  the  other  green.     The  mains  are 
so  laid  out  that  at  nearly  all  intersections  of  streets  hydrants  of 
both  colors  are  available. 


480  DISCUSSION 

9  Should  a  break  occur  in  either  system,  the  operator  at  the 
pumping  station  would  at  once  know  in  which  system  the  trouble 
was  located  by  looking  at  the  venturi  meters,  and  by  throwing  a 
switch  he  would  start  the  closing  of  two  electrically  driven  valves, 
separating  one  system  from  the  other.     Hydrants  would  then  be 
available  and  in  service  pending  the  location  and  isolation  of  the 
damaged  section. 

10  The  section  now  hi  operation  was  designed  to  give  20,000 
gal.  per  min.  on  any  one  block  with  a  loss  due  to  friction  from  pumps 
to  hydrant  not  to  exceed  40  Ib.     The  duplex  extension  will  give 
the  same  results,  and  should  either  half  be  out  of  service  by  an  acci- 
dent, there  will  still  be  available  at  the  same  location  10,000  gal.  per 
min.,  with  a  loss  from  the  pumps  to  the  hydrant  in  the  most  unfavor- 
able location  not  exceeding  50  Ib. 

RICHARD  H.  RICE.  This  paper  shows  that  the  installation  de- 
scribed was  made  after  the  most  careful  study  and  a  very  intelligent 
choice  of  the  types  of  apparatus  to  be  used.  The  choice  of  the 
centrifugal  pump  for  the  work  described  is  thoroughly  justified  by 
its  simplicity  and  by  the  efficiencies  obtained.  The  centrifugal  pump 
is  today  the  popular  means  of  producing  pressure  for  emergency  fire 
purposes,  as  in  the  fire  boats  of  New  York,  Chicago,  Duluth  and  San 
Francisco,  and  the  new  high-pressure  service  of  San  Francisco.  In  San 
Francisco  twelve  of  these  pumps  are  now  being  installed,  four  on  fire 
boats  and  eight  for  an  auxiliary  fire  installation.  On  the  fire  boats 
centrifugal  pumps  are  particularly  adaptable  as  they  can  be  run  in 
series  or  in  parallel.  In  parallel  they  give  150  Ib.  pressure,  and  in 
series  the  pressure  is  doubled.  This  pressure  is  particularly  valuable 
where  walls  have  to  be  battered  down,  or  streams  thrown  long 
distances. 

2  The  choice  of  alternating  current  as  the  source  of  power,  in  view 
of  the  unlimited  supply  of  current  existing  and  the  duplicate  means  of 
conducting  it  into  the  station,  is  also  justified.     In  cases  where 
electricity  is  not  so  available  as  it  is  in  New  York,  steam  turbines 
are  being  installed,  and  they  offer  advantages  over  the  gas  engine, 
where  maximum  reliability  is  considered. 

3  As  an  emergency  installation  pure  and  simple,  I  think  the 
installation  mentioned  in  the  paper  can  be  still  further  simplified. 
I  believe  the  speeds  chosen  for  operating  the  pumps  are  too  low, 
and  that  the  pumps  contain  too  many  stages.     I  have  had  occasion 
to  make  extensive  researches  in  centrifugal  pump  design  with  special 


HIGH-PRESSURE    FIRE-SERVICE    PUMPS  481 

reference  to  operation  at  steam-turbine  speeds,  and  have  found  that 
they  can  be  operated  at  high  speeds  with  a  smaller  number  of 
stages,  giving  efficiencies  comparable  with  those  obtained  here, 
although  the  question  of  efficiency  is  subsidiary  to  reliability  for 
this  service.  Pumps  for  this  service  should  be  designed  with  two  or 
three  stages  at  the  most,  and  with  considerably  higher  speed. 

4  Pumps  can  also  be  designed  without  balancing  pistons,  which 
are  undesirable  from  the  viewpoint  of  possible  interruption  of  service. 
An  inspection  of  Fig.  5,  illustrating  the  construction  of  the  pumps, 
will  show  that  the  balancing  pistons  used  are  quite  liable  to  damage 
if  water  containing  sand  or  other  impurities  is  used,  and  this  damage 
would  very  probably  result  in  stoppage  of  the  pump  when  it  is 
badly  needed.  The  use  of  balancing  pistons  is  unnecessary  in  such 
emergency  apparatus  and  should  be  avoided. 

C.  A.  HAGUE.  A  question  has  been  asked  several  times  with 
reference  to  the  results  of  tests  of  efficiency  on  centrifugal  pumps 
operating  singly  and  in  multiple  or  group.  Professor  Carpenter 
has  given  the  very  plausible  explanation  that  the  difference  in  effi- 
ciency in  favor  of  the  pumps  running  singly  is  probably  due  to  the 
presence  of  eddies  and  disturbances  in  the  pipes  when  the  pumps 
are  operating  together  and  the  absence  of  such  eddies  and  disturb- 
ances when  only  one  pump  is  at  work.  In  my  experience  in  installing 
pumps  and  condensers  singly  and  in  groups  I  have  found  them 
extremely  sensitive  to  each  other  in  operation,  both  in  taking  in 
and  discharging  the  water,  when  more  than  one  pump  is  working  on 
a  line. 

2  In  the  Manhattan  stations,  it  seems  to  me  that  the  suction  or 
inlet  pipes  and  the  discharge  pipes  are  coupled  too  closely  for  best 
efficiency;  and  also  that  the  inlet  pipe  close  to  the  pumps  is  not  large 
enough  for  operation  in  multiple,  although  perhaps   ample   for   a 
single  pump  when  the  water  is  undisturbed  by  the  draft  and  dis- 
charge of  several   pumps.     I   have  experimented  considerably   in 
that  line,  and  have  found  that  a  comparatively  large  body  of  water 
next  to  the  pumps  on  the  suction  side  will  materially  ease  the  machines 
in  their  performance.     The  idea  is  to  come  up  to  the  building  with  a 
normal  supply  pipe,  and  then  enlarge  it  very  considerably  just  where 
it  enters  the  building,  providing  the  inlet  pipe  with  a  good-sized  air 
chamber  wherever  possible.     I  have  tried  this  several  tunes  with 
excellent  results. 

3  Mr.  Brown  mentioned  the  difficulty  of  cutting  in  with  a  second 


482  DISCUSSION 

pump  where  the  first  pump  was  already  running,  a  difficulty  which 
I  think  is  also  due  to  too  close  connections  along  the  inlet  and  outlet 
lines  and  a  cramped  conditior  generally.  Of  course,  a  disturbance  [in 
the  water  column  and  in  the  hydraulic  horsepower  would  unbalance 
the  electric  power  to  a  certain  extent,  perhaps  not  much,  but  the 
total  disturbance  may  very  easily  result  Lin  the  loss  of  several  points 
in  the  efficiency. 

4  Considering  the  fact  that  the  city  pays  by  the  kilowatt-hour 
for  its  electric  current  as  per  switchboard  reading,  it  would  be  no 
more  than  proper  to  state  the  efficiency  of  kthe  machine  as  a  whole, 
and  not  exclusively  upon  the  basis  of  motor  efficiency  obtained  in 
the  shop  of  the  makers  a  thousand  miles  or  so  away.     In  this  case 
when  100  h.p.  in  current  is  supplied  to  the  switchboard,  the  motor 
has  shown  an  output  by  a  competent  test  of  93.2  h.p.  (Par.  37) ,  the 
balance  of  6.8  h.p.,  charged  against  the  city  in  the  power  bills,  being 
lost  in  heat  and  friction.    Then,  all  that  is  charged   against  the 
pump  is  93.2  h.p.    The  67.57  h.p.  shown  by  the  pump  for  each  100 
h.p.  at  the  switchboard  indicates  only  67.57  per  cent  total  efficiency, 
although  the  67.57  h.p.  indicates  72.5  per  cent  efficiency  of  the  power 
delivered  by  the  motor.     I  have  tested  several  centrifugal  pumping 
plants  of  various  sizes  and  powers,  and  the  total  efficiency  generally 
shows  from  64.5  per  cent  to  about  68  per  cent  and  very  seldom  above 
the  latter  figure. 

5  Mr.  Bibbins  touched  upon  ^the  possibilities  of  utilizing  the 
centrifugal  pump  for  waterworks  service,  but  uponj  investigation 
he  would  find  a  vast  difference  between  emergency  service,  where 
operating  economy  counts  for  little  in  the  face  of  great  danger  from 
fire,  and  the  steady  and  necessarily  economical  service  required  for 
the  continual  pumping  in  waterworks  stations.     To  show  how  decep- 
tive a  portion  of  the  truth  may  be,  a  case  is  cited  where  a  pumpage 
of  a  capacity  of  10,000,000  gal.  per  day  against  110  Ib.  load  could 
easily  be  accomplished  with  displacement  steam  machinery  by  an 
expenditure  of  $10,000  per  annum  for  coal.    But  an  attempt  to 
drive  centrifugal  pumps  by  electricity  resulted  in  a  cost  for  electrical 
power,  at  $6.50  per  1,000,000  gal.,  of  $23,725  per  annum;  showing  a 
difference  hi  favor   of    displacement    steam    machinery    equal    to 
5   per   cent   per   annum   on   $275,940.     There   is   no   conceivable 
difference  hi  cost  of  machinery,  buildings,  maintenance,  attendance, 
or  anything  else,  that  would  justify  such  a  preference  for  electricity 
and  centrifugal  pumps  over  steam  and  displacement  pumps.     Note 
the  following  figures: 


HIGH-PRESSURE    FIRE-SERVICE    PUMPS  483 

10,000,000  gal.  daily,  against  110  Ib 440  pump-h.p. 

120,000,000  steam  duty  with  8  Ib.  evaporation  in  the 

boilers,  coal  at  $2.50  per  net  ton  delivered $9928  per  annum 

Electric  power  at  $6.50  per  1,000,000  gal.  against  110  Ib. 

means  3,650,000,000  gal.  per  annum  at  $6.50 $23,725  per  annum 

The  difference  in  cost  for  the  element  of  power  is  $13,797 

per  annum,  which  at  5  per  cent  would  capitalize  at $275,940 

6  The  steam-driven,  reciprocating,  displacement  pumping  engine 
can  show  a  mechanical  efficiency  from  the  power  put  in  through  the 
throttle  to  the  water-horsepower  of  the  pumps,  as  high  as  96  per 
cent,  never  as  low  as  90  per  cent,  under  the  above  conditions.  The 
centrifugal  pump  when  steam-driven  has  a  corresponding  efficiency 
of  about  65  per  cent,  and  when  electrically  driven  of  about  67  per 
cent.  A  comparison  of  tests  is  given  in  Tables  1  and  2  in  which  it 
will  be  seen  that  the  steam  plant  saves  enough  to  pay  8.6  per  cent 
on  its  entire  cost. 

TABLE  1     COST  OF  OWNING  AND  PUMPING  WITH  HIGHEST  TYPE 
AND  CLASS  OF  STEAM  PUMPING  MACHINERY 

ONE  UNIT,  STEAM-DRIVEN,  RECIPROCATING,  DISPLACEMENT  MACHINERY, 
CAPACITY  OF  25,000,000  GAL.  AGAINST  87  LB. 

Pump  horsepower 870 

Boiler  horsepower  for  triple-expansion  vertical  pumping  engine 450 

Engine  house  and  foundations  and  engine  foundations 1 

Boiler  house  and  foundation,  boiler  foundations,  chimney,  etc 


Vertical  triple-expansion  pumping  engine. 

450  h.p.  of  boilers 

Building  for  coal  supply 


$150,000 


CHARGES   AGAINST   PLANT — PUMPING   ENGINE 

Interest 4  per  cent 

Sinking  fund 5  per  cent 

Depreciation 2  per  cent 

Oil  waste,  etc 1  per  cent 


Total • 12  per  cent 


CHARGES    AGAINST    PLANT BOILERS 


Interest 4  per  cent 

Sinking  fund 5  per  cent 

Depreciation 5  per  cent 


Total 14  per  cent 

3  engineers.     6  firemen.     3  oilers. 
Coal^at  $2.10  per  net  ton 


484  DISCUSSION 

SUMMARY  FOR  STEAM  RECIPROCATING  MACHINERY 

Coal  per  annum §11,957.40 

Wages  per  annum 9,900.00 

Capital  charges  on  engine 13,920.00 

Capital  charges  on  boilers 1,260.00 

Capital  charges  on  buildings 1,548.00 


Total  charges  per  annum $38,585 . 40 

Cost  per  1,000,000  gal $4.11 

Cost  per  horsepower 43 . 16 


TABLE  2    COST  OF  OWNING  AND  PUMPING  WITH  HIGHEST  TYPE 
ELECTRO-TURBINE  PUMPING  MACHINERY 

ONE  UNIT,  ELECTRIC-DRIVEN,  CENTRIFUGAL  MACHINERY,  CAPACITY  25,000,000 

GAL.  AGAINST  87  LB. 

Pump  horsepower 870 

Two-stage,  electric-driven  centrifugal  pump 

Engine  house  and  foundations  and  pump  foundations 

Transformer  house  and  foundations $43,750 

Transformers,  lightning  arresters,  conductors,  controllers  and  auxil- 
, dries. . ,  


CHARGES  AGAINST  PLANT — PUMPING  MACHINERY,  ETC. 

interest, 4  per  cent 

Sinking  fund 5  per  cent 

Oil,  waste,  etc 1  per  cent 

Depreciation 2  per  cent 

Total 12  per  cent 

3  Engineers.     3  Extra  men 
Electric  current,  $4.50  per  1,000,000  gal, 

SUMMARY  FOR  ELECTRO-TURBINE  MACHINERY 

Electric  current  per  annum $41,062 . 50 

Wages  perannum 5,700.00 

Capital  charges  on  machinery 4,314 . 00 

Capital  charges  on  buildings 468 . 00 


Total  charges  per  annum $51,544 . 50 

Cost  per  1,000,000 gal $5.64 

Cost  per  horse  power , , 59 . 24 


HIGH-PRESSURE    FIRE-SERVICE    PUMPS  485 

THOS.  J.  GANNON.  In  reply  to  Mr.  Hague  I  will  read  the  condi- 
ditions  which  occurred  on  the  evening  of  January  7,  when  both 
pumping  stations  were  put  to  a  crucial  test: 

7.22  First  alarm,  Hudson  and  Franklin  Sts. 

7.28  Second  alarm,  Hudson  and  Franklin  Sts. 

7.29  Third  alarm,  Hudson  and  Franklin  Sts. 
7.46  Fourth  alarm,  Hudson  and  Franklin  Sts. 
7.54  First  alarm,  Bowery  and  Hester  Sts. 
8.17  Automatic,  Mercer  and  Houston  Sts. 
8.19  Second  alarm,  Bowery  and  Hester  Sts. 
8.29  Second  alarm,  Mercer  and  Houston  Sts. 
8.32  Third  alarm,  Bowery  and  Hester  Sts. 
8.40  Third  alarm,  Mercer  and  Houston  Sts. 
8.43  Fourth  alarm,  Mercer  and  Houston  Sts. 
8.45  Fifth  alarm,  Mercer  and  Houston  Sts. 

2  In  due  time  seven  pumps  were  put  into  operation,  with  a  dis- 
charge which  reached  at  times  over  35,000  gal.  per  min.,  and  it  was 
estimated  that  over  52  fire  streams  were  in  service  at  the  same  time. 
Each  pump  responded  instantly  and  remained  in  service  until  ordered 
shut  down.  The  pressure  was  ordered  gradually  increased  from  125 
Ib.  to  230  lb.,  where  it  was  maintained  throughout  the  greater  part 
of  the  time  that  the  fires  raged.  The  operating  force  at  each  pump- 
ing station  consisted  of  but  one  engineman,  one  oiler,  one  telephone 
operator  and  one  laborer. 

PROF.  GEORGE  F.  SEVER.  A  question  was  asked  as  to  the  feasi- 
bility of  using  the  storage  battery  capacity  to  invert  the*  rotaries 
and  provide  alternating  current,  to  be  spread  through  the  alternating- 
current  system  to  the  sub-stations,  and  from  those  to  provide  alter- 
nating current  to  the  pumping  stations.  In  our  preliminary  investi- 
gation, if  I  recall  the  facts  correctly,  we  were  assured  that  this  could 
be  done;  giving  us  another  feature  of  reliability  in  the  operation 
of  the  system.  If  the  Waterside  station  should  go  out  of  business, 
we  could  still  get  current  from  the  sub-station. 

A.  C.  PAULSMEIER.*  While  the  reasons  given  in  the  paper  for 
the  selection  of  electric-driven  turbine  pumps  do  not  coincide  with 
the  conclusions  as  to  reliability  that  have  been  reached  in  the  West, 
there  can  be  no  question  about  the  careful  study  given  by  the  engi- 
neers who  planned  the  high-pressure  fire  system  described. 

1  Chief  Engineer,  Byron  Jackson  Iron  Works,  San  Franciso,  Cal. 


486  DISCUSSION 

2  The  pumps  show  a  remarkable  efficiency,  and  one  of  the  principal 
points  that  should  commend  them  to  those  interested  is  their  great 
flexibility  as  to  capacity,  a  characteristic  that  every  fire  pump  should 
possess. 

3  The  eight  fire  pumps  now  being  built  for  the  City  of  San 
Francisco  are  of   a   combined  capacity  of  216,000  gal.  per  min., 
under  a  working  pressure  of  300  Ib.     Each  of  these  pumps  is  driven 
by  a  750-h.p.  Curtis  steam  turbine,  operating  at  a  normal  speed  of 
1800  r.p.m. 

4  In  addition  there  are  now  being  completed  four  fire  pumps 
for  the  boats  Dennis  Sullivan  and  David  Scannel,  of  an  aggregate 
capacity  of  9000  gal.  per  min.  under  300  Ib.  working  pressure,  or 
18,000  gal.  per  min.  under  150  Ib.  working  pressure,  the  pumps 
being  so  arranged  that  they  work  either   in  series  or  in  parallel. 
The  pumps  have  all  been  subjected  to  24-hr,  tests,  and  while  the 
data  on  these  tests  are  not  sufficiently  complete  for  publication, 
they   show  that  the  pumps  are  not  as  flexible  as  to  capacity,  or 
are  not  as  capable  of  pumping  an  excess  quantity  of  water,  as  are  the 
Manhattan  pumps.     The  reason  for  this  is  that  the  impellers  in 
the  San  Francisco  pumps  are  only   13 1  in.  in  diameter,  while  the 
inlet  to  the  impellers  is  less  than  10  in.  in  diameter,  this  opening 
being  further  restricted  by  the  pump  shaft,  so  that  it  is  impossible 
to  obtain  much  excess  water,  no  matter  how  much  below  the  normal 
the  discharge  pressure  is  carried. 

5  In  the  station  pumps  now  being  built  the  velocities  at  the 
entrance  to  the  impellers  have  been  somewhat  decreased,  although 
it  is  impossible  to  make  anything  like  the  excess  capacity  shown  by 
the  Manhattan  pumps,  which  have  impellers  of  such  a  size  that 
the  inlets  may  be  made  anything  consistent  with  good  practice. 

PROF.  W.  B.  GREGORY.  It  is  gratifying  to  know  that  efficiencies 
ranging  from  70  to  80  per  cent  may  be  obtained  with  well-designed 
five-stage  turbine  pumps.  The  high-pressure  fire-service  pumps  in 
New  York  represent  one  extreme  of  conditions,  while  at  the  other 
extreme  is  the  centrifugal  pump  used  in  the  rice  irrigation  territory 
of  Louisiana  and  Texas  for  raising  large  quantities  of  water  through 
comparatively  small  lifts. 

2  The  improvement  in  design  of  pumps  of  the  latter  class  in 
the  last  ten  years,  and  especially  in  the  last  five  years,  has  made  it 
possible  to  specify  an  efficienc}'  of  75  per  cent,  even  with  heads  as 
low  as  10  ft.  Purchasers  of  pumping  plants  in  this  section  are  no 


HIGH-PRESSURE    FIRE-SERVICE    PUMPS 


487 


longer  satisfied  with    pumping  outfits  having  efficiencies  ranging 
from  50  to  60  per  sent. 

3  As  examples  of  the  results  obtained  with  pumps  of  the  class 
that  deals  with  large  volumes  of  water,  the  tables  are  quoted  from 
recent  acceptance  tests  conducted  by  the  writer,  of  pumping  plants 
used  for  rice  irrigation. 


TABLE   1     ACCEPTANCE  TESTS 

TANDEM-COMPOUND  CONDENSING  ENGINES,  DIRECT-CONNECTED 
Cane  and  Rice  Belt  Irrigating  Company,  Fulshear,  Texas,  August  12  and  14,  1908 


WORTHINGTON  PUMPS 


FIRST 
LIFT 


SECOND 
LIFT 


Size  of  pump  (diameter  discharge  pipe),  in 45  \           45 

Water  pumped,  gal.  per  min .^ 47,620  46,430 

Head  on  pump,  ft 33.90  13.95 

Efficiency  of  engine  and  pump,  % 69 . 5  73 . 6 

Efficiency  of  pump(engine93  %) 74 . 7  /9 . 2 

CROSS-COMPOUND  CONDENSING  CORLISS  ENGINE,  DIRECT-CONNECTED 
Sabine  Canal  Company,  Vinton,  La.,  May  22,  1909 

WORTHINGTON  PUMP 

Size  of  pump  (diameter  discharge  pipe),  in 45 

Water  pumped,  gal.  per  min 44.010 

Head  on  pump,  ft 23 . 26 

Efficiency  of  engine  and  pump,  % >9 . 5 

Efficiency  of  pump  (engine  90%) 77.3 

TANDEM-COMPOUND  CONDENSING  CORLISS  ENGINE,  DIRECT-CONNECTED^ 
Second  Lift,  Neches  Canal,  July  16,  1909 

MORRIS  MACHINE  WORKS  PUMP 

Size  of  pump  (diameter  of  discharge  pipe),  in 48 

Water  pumped,  gal.  per  min 60,300 

Head  on  pump,  ft 10. 12 

Efficiency  of  engine  and  pump  (maximum),  % 69 . 0 

Efficiency  of  pump  (engine  efficiency  93.2  %  max.) 75 


CHARLES  B.  REARICK.  Electrically  driven  fire  pumping-stations 
for  large  cities  are  dependent  upon  current  from  an  outside  source, 
usually  a  large  central  power  plant.  It  would  seem  quite  practicable 
in  many  cases  to  locate  new  fire  pumping  stations  adjacent  to  some 
large  power  plant  having  considerable  boiler  capacity.  In  such 
cases  it  would  be  possible  to  drive  the  centrifugal  or  turbine  pumps 
with  steam  turbines,  and  thus  eliminate  the  necessity  of  large  over- 


488  DISCUSSION 

load  capacity  in  electric  generating  units  for  the  central  station,  and 
also  the  liability  of  derangement  of  the  lines  between  the  power 
stations  and  the  pumping  stations.  The  charge  for  standby  service 
per  annum  should  be  less  than  for  similar  electric  service. 

2  The  steam  turbines  have  the  advantage  of  being  operative  at 
any  speed,  and  in  this  manner  will  maintain  in  the  discharge  mains 
any  pressure  desired.    Furthermore,  automatic  regulating  valves  can 
be  used  in  connection  with  the  turbine  to  maintain  constant  pressure 
irrespective  of  demand  or  flow. 

3  It  is  probable  that  the  cost  of  installation  would  be  less  than 
for  electric-driven  units.    The  turbine  could  run  non-condensing,  as 
the  question  of  steam  consumption  is  of  small  moment  for  fire  service. 

HENRY  E.  LONGWELL.  The  last  paragraph  of  the  paper  furnishes 
a  striking  illustration  of  how  purely  academic  is  the  ordinary  official 
efficiency  test,  and  of  how  little  value  as  a  basis  on  which  to  predicate 
the  results  that  may  be  expected  when  the  plant  is  operated  under 
service  conditions. 

2  This  paragraph  gives  general  figures  on  the  performance  of  the 
pumps  during  the  fire  run.  There  were  14,095,000  gal.  pumped, 
with  a  current  consumption  of  81,450  kw-hr.  The  aver  age -net  pres- 
sure against  which  the  pumps  operated  is  not  stated,  but  assuming 
it  was  300  lb.  per  sq.  in.,  the  pump  efficiency,  after  allowing  for 
the  losses  in  the  motor,  would  be  only  40  per  cent.  However,  we 
know  that  for  part  of  the  time  the  pressure  did  not  exceed  225  lb., 
or,  considering  the  pressure  in  the  suction  mains,  about  200  lb. 
net.  If  the  entire  quantity  of  water  had  been  pumped  against  this 
lower  pressure,  the  [efficiency  would  be  well  under  30  per  cent. 
It  is  therefore  perhaps  fair  to  assume  that  the  actual  average  effi- 
ciency was  not  far  from  35  or  36  per  cent,  or  say,  in  round  numbers, 
only  one-half  that  shown  on  the  official  test,  when  the  load  and  other 
conditions  of  operation  were  more  favorable. 

W.  M.  FLEMING.  With  the  rapidly  increasing  size  and  height  of 
office  buildings,  the  annual  fire  loss  in  the  business  districts  of  the 
cities  of  the  United  States  is  increasing  to  an  alarming  extent.  The 
installation  of  these  tremendously  effective  fire-fighting  systems  has 
already  proved  of  definite  value  in  the  reduction  of  city  fire  losses, 
and  consequently  of  insurance  costs. 

2  What  was  probably  the  pioneer  large  and  independent  so- 
called  high-pressure  fire  system  in  this  country  was  installed  at 


HIGH-PRESSURE    FIRE-SERVICE    PUMPS 


489 


490  DISCUSSION 

Philadelphia  in  1903-1904.  This  plant  differs  in  almost  every 
important  detail  from  the  New  York  system  more  recently  installed ; 
yet  the  general  results  in  each  case  have  been  excellent.  In  Phila- 
delphia the  plant  has  so  many  times  proved  of  great  value  in  actual 
service  that  a  much  larger  fire-fighting  system,  consisting  of  pump- 
ing units  identical  with  those  originally  selected,  is  now  being  installed 
to  protect  what  is  known  as  the  Kensington  mill  district. 

3  From   the   original   Philadelphia   station    at   Delaware    Ave. 
and  Race  St.,  a  location  unlikely  to  be  seriously  injured  by  con- 
flagration, Delaware  River  water  is  supplied  to  independent  high- 
pressure  fire-service  mains  which  effectually  cover  more  than  425 
acres  at  the  center  of  the  business  district.     The  pumping  units 
consist  of  vertical  double-acting  triplex  power  pumps  built  by  the 
Deane  Steam  Pump  Company,  direct-connected  to   Westinghouse 
vertical  3-cylinder  4-cycle  gas  engines  each  of  280  h.p.     The  seven 
large  pumping  units  have  each  a  nominal  capacity  of  1200  U.  S. 
gal.  per  min.,  at  300-lb.  pressure,  and  two  small  units  have  a  capacity 
of  350  U.  S.  gal.  at  the  same  pressure. 

4  The  general  arrangement  of  the  Philadelphia  pumping  station 
is  similar  to  that  of  the  large  New  York  installations     (Fig.   1). 
Two  rows  of  pumping  units  occupy  the  main  floor  of  the  station. 
The  pumps  are  nearest  the  center,  and  the  gas  engines  are  located 
hi  the  same  relative  positions  thereto  as  the  motors  in  the  New  York 
pump  houses.     A  platform  extending  along  the  sides  of  the  building, 
about  ten  feet  above  the  floor,  serves  as  a  working  gallery  for  the 
operation  of  the  engine  throttles.     Space  is  provided  for  the  installa- 
tion of  three  additional  pumping  units,  and  all  mains  are  propor- 
tioned with  the  ultimate  probable  capacity  of  the  plant  in  view. 
Suitable  connections  are  provided  to  the  mains  so  that  the  capacity 
of  the  pumping  station  may  be  supplemented  by  the  use  of  the 
city's  powerful  fire  boats,  should  occasion  require. 

5  The  internal -combustion  engines  are  of  the  well-known  standard 
Westinghouse  type  and  require  little  explanation.     Speed  regulation 
with  varying  loads  is  accomplished  by  the  action  of  a  centrifugal 
governor  controlling  the  quantity  of  combustible  admitted  to  the 
cylinders.    Ignition  is  by  a  very  neat  type  of  make-and-break  mecha- 
nism contained  in  a  cylindrical  plug.     Two  independent  igniters  are 
provided  in"each  cylinder,  and  three  independent  sources  of  ignition 
current  are^available  at  all  times.     The  engines  are  started  by  the 
use  of  compressed  air,  which  is  admitted  to  one  of  the  cylinders  at 
the  proper  time  to  secure  rotation  in  the  direction  required  until  the 


HIGH-PRESSURE    FIRE-SERVICE    PUMPS 


491 


regular  cycle  of  operation  is  established.     The  pumps  are  started 
under  no-load. 

6  The  pumps  are  of  the  vertical,  double-acting  piston,  triplex 
power  type,  requiring  comparatively  small  floor  space  and  giving  a 
rate  of  discharge  so  smooth  and  uniform  as  to  make  imperceptible  at 
the  hose  nozzles  any  pulsation  in  pressure. 

7  In  Fig.  2  is  a  sectional  view  of  one  of  the  pumps,  indicating  quite 
clearly  the  extreme  simplicity  and  accessibility  of  the  machine, 
and  its  general  construction.     All  valves  are  of  the  poppet  type, 
readily   accessible  through   handhole   openings.     Valve   areas    and 
waterways  naturally  are  comparatively  large,  so  that  friction  losses 


FIG.   2     SIDE  AND  SECTIONAL  END   ELEVATION  OF  TRIPLEX  PUMPS  *OR  THE 
PHILADELPHIA  HIGH-PRESSURE  FIRE-PUMPING  STATION 

are  reduced  to  a  minimum.  The  water  ends  are  thoroughly  brass- 
fitted  in  order  that  the  pumps  may  be  readily  started  after  a  long 
period  of  disuse. 

8  There  is  a  connection  through  a  12-in.  check  valve,  from  the 
city  mains  to  the  high-pressure  system,  so  that  the  mains  and  pumps 
are  constantly  primed  with  a  pressure  of  60  Ib.  and  are  ready  for 
service  at  all  times.  A  complete  system  of  fire-alarm  boxes  and  tele- 
phones, with  underground  wires,  permits  direct  communication 
between  the  vicinity  of  any  fire  and  the  pumping  station.  On  the 
sounding  of  the  alarm,  the  station  force,  consisting  of  an  engineer 
and  his  assistant,  can  bring  the  total  plant  of  seven  large  units 


492  DISCUSSION 

into  service  in  seven  minutes,  and  have  repeatedly  done  so.  Work- 
ing pressure  is  invariably  available  at  the  hydrants  one  minute 
from  the  time  of  the  alarm.  Such  a  result  would  be  impossible 
with  ordinary  movable  apparatus. 

9  The  pumping  units  are  started  up  under    no-load,   by   the 
use  of  a  motor-driven  by-pass  valve,  through  which  the  pump  dis- 
charges into  an  overflow,  until  the  normal  cycle  of  operations  has  been 
set  up  in  the  gas  engine,  when  the  switch  is  closed,  causing  the  by- 
pass valve  to  close  and  the  discharge  to  be  directed  into  the  fire  mains. 

10  Experience  has  indicated  that  the  maximum  pressure  of  300 
Ib.  is  required  only  for  the  most  extensive  fires,  and  for  fires  in  the 
higher  parts  of  tall  buildings.     The  pressure  records  show  that 
probably  75  per  cent  of  the  water  pumped  is  required  at  not  more 
than  150  Ib.  to  175  Ib.  pressure.     The  pressure  desired  in  each  case, 
is  dictated  over  the  telephone  by  the  fire  chief,  the  required  pressure 
regulation  being  obtained  by  proportioning  the  number  of  units  in 
operation  to  the  requirements. 

11  The  practical  results  of  the  use  of  the  Philadelphia  fire  system 
have  been:  material  reduction  in  fire  losses  in  the  protected  district, 
large  decrease  in  fire  insurance  rates,  and  a  greater  willingness  on 
the  part  of  property  owners  in  the  protected  section  to  erect  pre- 
tentious office  buildings. 

12  Though  the  writer  is  unable  to  present  a  statement  as  to 
the  annual  saving  to  property  owners  by  the  installation,  yet  in 
view  of  the  low  cost  of  operation  of  the  plant,  there  can  be  no  question 
but  that  it  presents  a  considerable  yearly  saving  to  the  city.    During 
the  year  1907,  which  is  perhaps  typical,  water  was  delivered  to  16 
fires,  the  longest  one  lasting  44  hr.     The  plant  responded  to  1 16  alarms 
at  which  no  service  was  required.     The  operating  expenses  for  the 
year  were  as  follows: 

Gas;  839,488 cu.  ft.  at  $1.00 $839.49 

Electric  lighting 343.99 

Electric  power 7 . 98 

65  tons  pea  coal  at  $3.50 227.50 

Supplies  furnished  the  pumping  station  for  the  entire  year  1907 1,500 . 00 


Total  fixed  charges  for  1907 $2,918-96 

SUMMARY 

Salaries  (Total  for  entire  staff) $8,389.72 

Total  cost  materials 2,918 . 96 


Total  operating  expenses $11,308 , 68 

Total  daily  maintenance  charge,  salaries  and  operation $31 . 12 


HIGH-PRESSURE  FIRE-SERVICE  PUMPS  493 

13  No  mechanical  defects  have  yet  developed  in  either  engines 
or  pumps,  and  practically  the  only  replacements  have  been  a  few 
rubber  valves  for  the  pumps  and  ignition  details  for  the  engines. 

14  While  no  definite  comparison  can  be  made  between  the  small 
plant  in  Philadelphia  and  the  comparatively  large  plants  in  New 
York,  which  have  not  yet  been  in  operation  for  an  appreciable  length 
of    time,  the  operating  expenses  of  the  Philadelphia  plant  seem 
likely  to  prove  much  less  for  a  given  quantity  of  service.     This  *s 
largely  due  to  the  so-called  "readiness-to-serve"  charge  made  by  the 
company  furnishing  power  to  the  New  York  plants.     To  this  charge 
must,  of  course,  be  added  the  cost  of  the  current  actually  consumed. 

15  Unfortunately  no  mechanical  efficiency  test  has  ever  been 
made  on  any  of  the  Philadelphia  pumping  units.    Judging  from 
tests  of  similar  machinery,  an  efficiency  of  80  to  85  per  cent  is  to  be 
expected  from  pumps  of  this  character  operating  against  150  to  200 
Ib.  pressure.     If  this  is  the  case,  knowing  that  75  to  80  per  cent  of  the 
water  to  be  used  will  be  required  at  pressures  not  to  exceed  175  Ib., 
it  would  seem  that  the  plant  efficiency  in  Philadelphia  would  prove 
greater  than  in  New  York,  where  we  understand  that  the  water  must 
be  delivered  through  reducing  valves  from  300  Ib.  to  any   lower 
pressure  required. 

DISCUSSION  AT  ST.  LOUIS 

HORACE  S.  BAKER*  presented  some  very  complete  notes  on  the 
proposed  high-pressure  system  for  Chicago,  an  abstract  of  which  is 
given  herewith.^After  telling  of  that  city's  need  of  a  high-pressure 
system,  Mr.  Baker  illustrated  the  effect  of  such  an  installation  on 
insurance  rates  by  citing  the  reductions  brought  about  in  other 
cities,  details  of  which  are  given  in  Table  1,  herewith. 

2  The  costs  of  maintaining  and  operating  the  proposed  system 
for  Chicago  should  not  be  more  than  the  following  figures,  and  prob- 
ably much  less: 

Operating  costs  of   three  pumping   stations,  including  interest  and 

depreciation $180,000 

Interest  on  cost  of  distribution  system,  4  per  cent  of  $3,000,000 120,000 

Depreciation  of  distribution  system,  2  per  cent  of  $3,000,000 60,000 

Maintenance  of  distribution  system 50,000 

$410,000 
1  Engineer,  Department  of  Public  Works,  Chicago. 


494 


DISCUSSION 


HIGH-PRESSURE   FIRE-SERVICE   PUMPS 


495 


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496  DISCUSSION 

TABLE  2     COST  DATA  FOR  VARIOUS  TYPES  OF  APPARATUS 


NAME  OF  SYSTEM 

TYPE 

i! 
ll 

si 

• 

TOTAL  COST  EXCEPT 
DISTRIBUTION  SYS- 
TEM 

ANNUAL  OPERATING 
EXPENSE  OP  PUMP- 
ING STATIONS1 

COST  PER  1000  GAL. 
PER  MIN.  CAPACITY1 

ANNUAL  OPERATING 
COST  PER  1000  GAL. 
PER  MIN.  CAPACITY1 

Nfn.nlifi.Hfln 

f  Electric  

300  lb. 

fVm»w  TalnnH 

\  Centrifugal  Pumps  

30,000  gal. 
150  lb. 

$670,000 

$139,250 

$22,333 

$4,642 

\  Triplex  Pumps 

4  500  gal 

47  000 

14  186 

10  444 

31    *»2 

Ph51«.fl*>lnVilfi 

/  Gas  Engines  

300  lb. 

\  Triplex  Pumps  

9  100  gal. 

260000 

11  978 

28  571 

1  316 

f  Steam  Turbines  

300  lb 

San  Francisco.  .  .  .  .  . 

Estimate  1  

20,000  gal. 

622,228 

34,630 

31,111 

1,732 

[Oil  Fuel  . 

San  Francisco          . 

f  Gasolene  Engines  

300  lb. 

Estimate  2 

•1  Turbine  Pumps  

20,000  gal. 

737,848 

30,595 

36,892 

1,529 

[  Rope  Drive  

Hertford 

f  Steam  Turbines  

300  lb. 

Estimate  1  

•1  Centrifugal  Pumps.  .  .  . 

12,600  gal. 

257,620 

45,320 

20,466 

3,597 

[  Coal  Fuel..     . 

Hartford  

f  Gas  Engines  

300  lb 

Estimate  2 

\  Triplex  Pumps 

12  600  gal 

377  905 

o  RAO 

29  992 

fiSB 

J  Steam  Turbines  

250  lb 

\  Centrifugal  Pumps  
/  Gas  Engines                 . 

10,000  gal. 
250  lb 

263,005 

37,400 

26,300 

3,740 

\  Triplex  Pumps  

10  000  gal 

248  112 

24626 

248H 

2  463 

f  Electric  Motors  

250  lb 

\  Centrifugal  Pumps.  .  .  . 

10,000  gal. 

122,882 

57,700 

12,288 

5,770 

1  Exclusive  of  Interest  and  Depreciation. 

3  In  the- light  of  current  practice  as  shown  in  Table  2,  it  seems 
advisable  to  consider  and  estimate  on  the  following  types  of  pumping 
stations: 

a  Steam  turbines  and  centrifugal  pumps. 

6  Electric  motors  and  centrifugal  pumps. 

c  Gas  engines  and  triplex  pumps. 


HIGH-PRESSURE  FIRE  SERVICE   PUMPS  497 

TABLE  3    STEAM  TURBINE  PUMPING  STATION 

APPROXIMATE  ESTIMATE  OF  COST 
Capacity  10,000  gal.  per  min.;  pressure  250  Ib  per  sq.  in. 

1  Excavation: 

Pump  pit 2300  cu.  yd. 

Boiler  room 3865  " 

Stack 565  "      " 

Conveyor  tunnel 70  "      " 

6800  cu.  yd.  at  $1  $6,800 

2  Concrete : 

Retaining  walls  for  pump  pit 616  cu.  yd. 

Boiler  room  foundations 453  "      " 

Stack  foundations 430  "      " 

Pump  house  foundation 101  "      " 

1600  cu.  yd.  at  $7  li.200 

3  Building: 

Pump  room,        60  ft.  by  54  ft.  =  3240  sq.  ft. 
Boiler  room,        78  ft.  by  84  ft.  =  6552    "      " 

P 
9792  sq.  ft. 

Assume  10,000  sq.  ft,  by  30  ft.  =  300,000  cu.  ft.  at  15  cents 45,000 

4  Foundations  for  pumps  and  turbines,  150  cu.  yd.  at  $10 1,500 

5  Four  2500-gal.  centrifugal  pumps  at  $5,000 20,000 

6  Four  600-h.p.  steam  turbines  at  $12,000 48,000 

7  Boilers,  2400  h.p.  at  $15 36,000 

8  Chain  grates,  hoppers,  conveyors,  etc 15,000 

9  Stack 8,000 

10  Suction  piping  from  city  main  and  tunnel 6,500 

11  Discharge  piping 5,000 

12  Steam  piping 7,500 

13  Condenser 6,200 

14  Boiler  auxiliaries,  heater,  purifier,  pumps,  etc 9,000 

15  Two  20-in.  venturi  meters  and  recorders 3,000 


$228,700 
Add  15  per  cent 34,305 

$263,005 
APPROXIMATE  ESTIMATE  OF  OPERATING  EXPENSE 

1  Interest,  4  percentof  $263,005 $10,520 

2  Depreciation,  4  per  cent  of  $263,005 10,520 

3  Coal: 

200  hr.,  5  tons  at  $2.50    \ 
8560  hr.,  |  ton    at    2.50    f"'  13'  °° 

4  Oil,  waste  and  supplies 1,500 

5  Repairs 2,500 

6  Labor: 

Men,  cost  per  annum  three  8-hr,  shifts: 

1  engineer $6600 

1  oiler 4500 

1  fireman 3000 

2  coal  passers 5400 

1  janitor 700 

20,200 

Total $58,440 


498  DISCUSSION 

TABLE  4    GAS-ENGINE  PUMPING  STATION 

APPROXIMATE  ESTIMATE  OP  COST 
Capacity  10,000  gal.  per  min. ;  pressure  250  Ibs. 

1     Excavation: 

Retaining  wall 68,400  cu  ft. 

Main  pit 58,089  "     " 

Engine  foundations 5,096  "     " 

Pump  foundations 7,056  "     " 

Tunnel ; 5,496  "     " 


144,137  cu.  ft. 
=     5,339  cu.  yd.  at  $1 , 
Concrete: 

Retaining  wall 11,520  cu.  ft. 

Retaining  wall  footing 23,040  "     " 


$5,339 


34,560  cu.  ft. 

=     1,280  cu.  yd.  at  $7 8,960 

3  Building:  82  ft.  by  79  ft.  by  30  ft.  =  19,430  cu.  ft.  at  15  cents  . .  29,151 

4  Foundations  for  pumps  and  engines,  450  cu.  yd.  at  $10 4,500 

5  Seven  1500-gal.  triplex  pumps,  for  250  Ib.  pressure  at  $8900 . .  62,300 

6  Seven  300-h.p.  gas  engines  at  $10,000 70,000 

7  Freight  and  erection 7,000 

8  Suction  pipes  from  city  main  and  tunnel 6,500 

9  Water  discharge  pipes 5,000 

10  Gas  connections 8,000 

11  Air  compressor  plant 2,500 

12  Gasolene  tanks  and  piping 3,500 

13  Two  20-in.  venturi  meters  and  recorders 3,000 

$215,750 

Add  15  per  cent 32,362 

$248,112 

ESTIMATE  OF  OPERATING  EXPENSE 

1  Interest,  4  per  cent  on  $248,112 $9,924 

2  Depreciation,  4  per  cent  on  $248,112 9,924 

3  Gas:     200  hr.  at  18  cu.  ft.  per  h.p.  at  $0. 85  per  M 6.426 

4  Labor:    3  engineers  at  $2200  =    $6600 

6  asst.  engrs.at  1500  =      9000 

1  janitor      at                        600  16,200 

5  Oil,  waste  and  supplies 1,000 

6  Repairs 1,000 

Total..  $44,474 


HIGH-PRESSURE  FIRE-SERVICE  PUMPS 


499 


TABLE  5    ELECTRIC  PUMPING  STATION 
APPROXIMATE  ESTIMATE  OF  COST 

Capacity  10,000  gal.  per  min.;  pressure  250  Ib.  per  sq.  in. 
Excavation: 

Pump  pit 63,936  cu.  ft. 

Retaining  wall  footings 8,640  "     " 

Pump  foundations 2,048  "     " 

Building  wall 1,692  "     " 


2,826  cu.  yd.  at  $1          $2,826 


76,316  u     "  = 
Concrete: 

Wall  of  pump  pit 15,264  cu.  ft. 

Footings 7,892  "     " 

Bldg.  foundation  wall 920  "     " 

Bldg.  foundation  footings 329  "     " 


24,405  cu.  ft. 

=  904  cu.  yd.  at  $7 6,328 

3      Building: 

Pump  room,  36  ft.  by  56  ft.    =     2016  sq.  ft. 
Switch  room,  16  ft.  by  56  ft.    =  896    sq.ft. 

2912  or  say  3000  sq.  ft. 

3000  sq.  ft.  by  30  ft.  =  90,000  cu.ft.  at  15  cents  13,50o 

4  Foundations  for  pumps  and  motors,  150  cu.  yd.  at  $10 1,500 

5  Four  2500-gal.  centrifugal  pumps  at  $5000 20,000 

6  Four  600-h.p.  3-phase  induction  motors  at  $10,800 43,200 

7  Suction  piping  from  city  main  and  tunnel 6,500 

8  Discharge  piping  and  valves  in  station 5,000 

9  Switchboard  and  wiring  in  station 5,000 

10    Two  20-in.  Venturi  meters  and  recorders 3,000 

$106,854 
Add  15  per  cent 16,028 

Total $122,882 

APPROXIMATE  ESTIMATE  OP  OPERATING  EXPENSE 

1  Interest,  4  per  cent  of  $122,882 $4,915 

2  Depreciation,  4.3  per  cent  of  $122,882 5,284 

3  Power  bill: 

Ready-to-serve  charge,  $25  per  kw.  =  $37,500 

$0 . 005  per  kw.  per  hr.,  200  hr.  of  full  load  $1,500 39,000 

4  Labor,  3  shifts: 

3  engineers $6600 

6  asst.  edgineers 9000 

1  janitor : 600  16,200 

5  Miscellaneous:  oil,  supplies,  etc 1,500 

6  Repairs 1,000 

$67,899 


500 


DISCUSSION 


TABLE  6    ESTIMATED  COST  OF  PROPOSED  CHICAGO  SYSTEM 
MAINS,  VALVES  AND  HTDRANTS 


DISTRICT  No. 

COST 

1  

J477  508 

2  

329  321 

3  

152  018 

4  

128  457 

5  

109  178 

6          ....                 ... 

314  569 

7 

82  791 

8  

178  420 

9  

146  432 

10  

118916 

11      

113268 

12  

85852 

13  

75918 

14  

175  811 

Totnl  

$2,488  459 

Engineering  and  contingencies  ... 

373  269 

4  stations  at  $250,000  —  

$2,861,728 
1  000  000 

$3,861,728 

No  allowance  made  for  land. 

River  crossings  are  assumed  to  be  made  as  follows:  (a)  North  branch  in  present  Grand  Ave. 
water  pipe  tunnel;  (6)  Main  River  in  proposed  LaSalle  St.  water  pipe  tunnel,  to  be  built  by 
Chicago  Railways  Company;  (c)  South  branch  in  present  Harrison  St.  water  pipe  tunnel. 


4  For  the  purpose  of  estimate  it  seems  proper  to  assume  a  station 
of  a  capacity  of  10,000  gal.  per  min.  against  250-lb.  pressure,  the 
working  pressure  to  be  probably  150  to  200  Ib.     To  avoid  the  crip- 
pling of  a  station  by  the  shutdown  of  any  unit  it  seems  advisable 
to  consider  units  of  2500  gal. 

5  In  discussing  the  various  types  of  installations  proposed,  Mr. 
Baker  cited  the  advantages  of  each  type.     The  direct-acting  duplex 
pumps  are  rugged  andj*eady  for  immediate  service,  but  their  steam 
consumption   is   large.*  The   independent   boiler    plant   necessary, 
moreover,  would  be  costly  to  build  and  to  operate. 

6  The  gas-engine  station  has  the  advantage  of  lower  first  cost, 
and  no  cost  for  power  when  not  in  operation.     Though  failure  of  the 
gas  supply  is  unlikely,  gasolene  could  be  used  with  a  change  of 


HIGH-PRESSURE   FIRE-SERVICE   PUMPS  501 

adjustment,  or  by  running  normally  on  illuminating  gas  with  low 
compression,  which  would  be  somewhat  uneconomical.  A  gas-pro- 
ducer plant  might  be  installed,  though  this  is  somewhat  open  to  the 
same  objection  as  the  boiler  plant. 

7  Though  electric  motors  are  supplied  from  an  outside  sources 
the  large  number  of  generating  stations  and  feeders  makes  the  electric, 
supply  as  reliable  as  the  gas  supply.     The  first  cost  and  the  operating 
expense  of  an  electric  station  are  low,  though  the  standby  charge  is 
high. 

8  Connecting  the^system  to  stand  pipes  and  to  the  sprinkler  systems 
in  buildings  had  been  recommended  in  Chicago  and  is  the  practice  in 
Winnipeg,  Man.,  and  Providence,  R.  I.,  and  also  with  the  gravity 
system  in  Newark,  N.  J.,  Worcester  and  Fitchburg,  Mass.     The  fire 
systems  of  New  York  City  and  Philadelphia  are  not  connected  in 
this  way.    The  objection  to  these  connections  is  that  great  loss  of 
water  might  result  from  broken  pipes  in  the  buildings.     This  could 
be  avoided,  however,  by  placing  a  controlling  valve  in  a  brick  chamber 
outside  the  curb. 

EDWARD  E.  WALL*  outlined  the  proposed  fire  system  for  St.  Louis, 
which  contemplates  the  installation  of  six  or  eight  5-stage  centrifugal 
pumps,  electrically  driven,  at  a  station  on  Chestnut  St.,  from  which 
the  fire  service  mains  will  radiate  north,  south  and  west.  The  supply 
for  these  pumps  will  be  taken  from  the  distribution  system,  a  36-in. 
main  being  laid  directly  from  the  Bissell's  Point  pumping  station 
to  the  Chestnut  St.  station,  and  connected  to  the  present  distribu- 
tion system  by  a  number  of  by-passes.  Connections  will  also  be 
made  between  two  20-in.  mains  on  Fourth  and  Seventh  Sts.,  to  the 
supply  for  the  pumps,  so  that  in  case  of  failure  of  the  36-in.  main, 
the  pumps  may  be  supplied  from  this  source. 

2  It  would  be  practicable  to  draw  the  fire  pump  supply  directly 
from  the  Mississippi  River  by  building  an  intake,  but  this  would 
probably  cost  more  than  the  laying  of  the  36-in.  main,  and  would 
necessitate  a  charter  from  the  Government.  It  would  also  raise  the 
question  of  obstructing  navigation,  since  it  would  be  necessary  to 
carry  the  construction  well  out  into  the  channel,  to  insure  an  ample 
supply  of  water.  Supply  from  the  river  direct  would  also  preclude  all 
connection  with  the  distribution  system,  as  it  would  be  unwise  to 
risk  the  contamination  of  the  city's  water  supply  by  river  water. 

1  Asst.  Water  Commissioner,  St.  Louis. 


502  DISCUSSION 

3  The  pumping  capacity  of  the  station  at  Bissell's  Point  will  be 
over    100,000,000]  gal.  of  water  every  twenty-four  hours,  which  is 
more  than  twice  the  amount  ordinarily  consumed;  the  excess  being 
sufficient  to  supply  more  than  30  fire-streams  through  3-in.  hose  con- 
tinuously, assuming  300-lb.  pressure  at  the  fire  pumps. 

4  The  5-stage  centrifugal  pumps  proposed  for  the  Chestnut  St. 
station  will  have  a  capacity  of  150,000  gal.  per  hr.  each,  against  a 
pressure  of  300  Ib.  per  sq.  in.     It  is  proposed  to  connect  the  station 
with  the  power  plants  of  the  Union  Electric  Light  and  Power  Com- 
pany and  the  United  Railways,  so  that  two  sources  for  power  will 
be  available. 

5  The  three  discharge  mains  from  these  pumps  will  be  24  in.  in 
diameter,  the  district  supplied  by  them  to  be  gridironed  by  a  system  of 
12-in.  mains  laid  on  the  enclosed  streets  and  occasionally  connected, 
at  crossings  only,  by  by-passes,  that  the  breakdown  of  one  main 
may  not  necessitate  the  cutting  out  of  any  other  line.     The  pipe 
used  will  be  cast  iron,  extra  heavy,  with  bell  and    spigot    joints, 
double-grooved.     All  fire-hydrant  leads  will  be  8  in.  in  diameter. 

6  The  system  will  be  under  the  ordinary  distribution  pressure 
when  the  fire  pumps  are  not  in  use,  so  that  for  small  fires  the  hydrants 
will  be  available  for  use;  when  the  fire  pressure  is  put  on  the  system, 
the  check  valves  on  the  by-passes  will  prevent  additional  pressure 
from  coming  on  the  distribution  system. 

7  While  the  arrangement  of  machinery  for  the  pumping  station, 
and  the  details  of  operation,  have  not  been  definitely  decided  upon, 
it  is  possible  that  gas  engines  may  be  used  instead  of  electric  motors. 
The  questions  of  automatically  starting  and  stopping  the  pumps, 
maintaining  the  pressure  during  a  fire,  and  the  general  details  of 
operation  of  the  station,  as  well  as  the  minor  points  of  weight  of 
pipe,  design  of  hydrants,  etc.,  have  all  to  be  worked  out.     It  is  esti- 
mated that  the  cost  of  this  system  will  approximate  $3,000,000. 

H.  C.  HENLBYI,  speaking  on  the  advantages  of  high-pressure  fire 
systems,  said  that  they  were  chiefly  valuable  for  the  numerous 
powerful  streams  which  can  be  quickly  brought  into  service  and  concen- 
trated to  advantage.  For  the  prevention  of  conflagrations  and  for 
keeping  serious  fires  from  spreading,  more  powerful  streams  are  needed 
than  can  be  supplied  by  portable  fire  engines  without  considerable  delay. 
To  obtain  such  streams  from  fire  engines,  it  is  necessary  to  " Siamese" 
two  or  more  lines  into  one  nozzle,  requiring  considerable  time;  and 

1  Chief  Inspector,  St.  Louis  Fire  Prevention  Bureau. 


HIGH-PRESSURE   FIRE-SERVICE   PUMPS 


503 


if  a  change  in  the  location  of  engines  becomes  necessary,  consider- 
able time  is  again  lost  in  re-assembling  the  hose  lines. 

2  The  high-pressure  system  permits  the  use  of  hose  of  large  diam- 
eter— 3  in.  and  3£  in. — and  direct  connection  to  hydrants  furnishes 
a  supply  to  nozzles  of  large  area,  without  the  necessity  of  siamesing 
two  or  more  hose  lines.  The  2-in.  nozzle  is  best  adapted  for  use 
with  high-pressure  systems,  this  nozzle,  under  75  Ib.  nozzle  pressure, 
discharging  approximately  1000  gal.  per  min.  A  nozzle  of  this 
area  provides  very  effective  service,  as  the  loss  of  pressure,  due  to 
friction  in  fire  hose,  decreases  as  the  area  of  the  hose  is  increased. 
The  data  given  in  the  table  are  derived  from  experiments  by  John 
R.  Freeman,  and  show  the  pressure  required  at  the  hydrant  in 

PRESSURE  REQUIRED  AT  HYDRANT  TO  OVERCOME  FRICTION  LOSS 


Hose  Diameter 

21  IN. 

3  IN. 

3*  IN. 

Hose  lines 

Single 

Siamesed 

Single   iSiamesed 

Single    Siamesed 

Smooth  bore  nozzle 

11  in. 

2  in. 

llin. 

2  in. 

It  in. 

2  in. 

100 

121 

139 

92 

101 

84.5 

88 

150 

139 

170 

99.5 

113 

87.5 

93.5 

Length  of  hose  line,  ft  

200 

158 

201 

107 

125 

91 

99 

250 

176.5 

232 

114.5 

137 

94.5 

104.o 

300 

195 

263 

122 

149 

98 

110 

400 

232 

325 

137 

173 

105 

121 

For  the  2-in.  nozzle  it  is  assumed  that  two  hose  lines  of  the  length  given  are  Siamesed  together. 

hose  streams  of  various  lengths,  to  overcome  friction  loss  and  main- 
tain 75-lb.  nozzle  pressure,  the  nozzle  being  at  the  same  level  as  the 
hydrant. 

3  High-pressure  systems  should  be  considered  as  auxiliary  protec- 
tion and  there  should  be  no  attempt  at  abandonment  of  engines 
or  other  apparatus. 

4  Direct   connection  from   a  high-pressure  system    to  interior 
standpipes,  sprinkler  equipments  and  open  sprinkler  systems,  should 
be  made  through  Siamese  connections  and  not  through  direct  pipe 
connection. 

5  The  inability  of  portable  steam  fire  engines  to  furnish  a  stream 
efficient  to  cope  with  serious  fires  is  made  apparent  by  tests  made 
by  the  engineers  of  the  National  Board  of  Fire  Underwriters.     The 
steam  fire  engines  for  test  were  picked  at  random  from  the  equipment 
of  many  of  the  best  city  fire  departments  in  the  country. 


504  DISCUSSION 

Number  of  engines  tested 102 

Nominal  capacity,  gal 69,800 

Actual  capacity,  gal 55,900 

Percentage  of  efficiency 80 

In  many  cases  the  efficiency  of  individual  "steamers"  is  less  than 
50  per  cent. 

EDWARD  FLAD.  It  appears  to  me  that  a  cast-iron  pipe  is  rather 
dangerous  for  high  pressure.  A  cast-iron  pipe  tested  under  300-lb. 
pressure  will  often  break  at  75  Ib.  A  "wrought  steel  pipe  is  much 
more  reliable,  and  if  properly  coated,  should  last  25  or  30  .years 
under  ordinary  conditions.  If  steel  pipe  is  absolutely  reliable  we 
can  afford  to  relay  it  at  the  end  of  25|  years^rather  thanrtoH  use 
cast-iron  pipe,  which  is  liable  to  break. 

2  In  answer  to  a  question  by  Mr.  Flad  as  to  the  flexibility  of Jthe 
joint  used  in  Baltimore,  Professor  Carpenter  replied  that  it  is  flexible, 
in  the  sense*  that  it  can  be  laid  at  an  angle;  it  is  not  flexible  so  far 
as  change  of  form  is  concerned. 

H.  S.  BAKER  asked  what  kind  of  steel  pipe  would  be  used  in  Balti- 
more, Professor  Carpenter  answering  that  it  is  extra  heavy  steel 
welded  pipe,  3^ -in.  thick,  the  ends  being  expanded  into  semi-spheres, 
an  8-in.  or  12-in.  pipe  being  expanded  just  enough  to  get  a  ring  in 
it,  and  the  whole  bolted  on  the  outside  by  external  bolts;  very  like 
a  steam  pipe. 

PROP.  H.  WADE  HIBBARD.  It  is  a  fact  that  a  cast-iron  water 
main  has  been  in  satisfactory  use  in  city  service  for  twenty  years 
and  then  a  piece  has  blown  out.  It  seems  to  me  that  the  use  of  cast- 
iron  pipe  should  be  prohibited  for  this  special  emergency  purpose  of 
fire  protection  on  account  of  its  unreliability.  In^  fact,'in  one  of  the 
high-pressure  systems  using  cast-iron  mains,  leaks  have  been  known 
to  take  place'and  the  pumps  to  run  for  a  considerable  interval,  some 
hours,  [I  will  say,  and  the  pressure  could  not  be  maintained  under 
test,  until  it  was  finally  discovered  that  the  water  had  been  pouring 
out  into  a  very  large  excavation  and  flooding  it,  unknown  to  those 
operating  the  pumping  station.  Steel  will  show  approaching  deteri- 

•  «  »  «ii  .     »  tfluH     "*!  "-*S— "-M  ~  S'^H^ITtijjni**  "*~-,tt*-$**^Hf*» ' 

oration  as  cast  iron  will  not.          ;    gg    .  ^^^  ii-SLiuiir, 

2    Steel  'pipe  ought  to'- be  good  for  thirtyfyears^ofj  service.  |  That 

period  of  service  should  be  sufficient,  and  cities  having  such  pipe 


HIGH-PRESSURE  FIRE-SERVICE   PUMPS  505 

hould  then  be  willing  to  replace  it,  having  had  more  reliable  protection 
during  that  period  of  years,  than  cast-iron  pipe  could  possibly  give. 

H.  C.  HENLEY  asked  if  there  had  been  any  attempt  made  to  pre- 
vent the  pipes  from  deteriorating  through  electrolysis,  Professor 
Carpenter  answering  that  the  Baltimore  system  is  a  continuous 
metallic  structure,  from  one  end  to  the  other,  and  he  believed  would 
be  thoroughly  protected  from  electrolysis;  or  at  least,  better  than  by 
any  other  system. 

E.  E.  WALL.  It  is  a  fact  that  actually  and  not  figuratively,  steel 
pipe  must  be  handled  with  gloves  when  it  is  laid,  because  the 
coating  has  to  be  very  carefully  preserved  and  can  hardly  be  repaired 
if  it  is  broken  in  handling  before  the  pipe  is  laid.  This  is  a  very 
serious  objection  to  the  laying  of  steel  pipe  on  account  of  exposure 
to  corrosion  after  it  is  laid. 

W.  H.  REEVES.  Owing  to  the  magnitude  and  prominence  of  these 
plants,  the  pump  performances  should  be  of  interest  to  those  desiring 
information  on  centrifugal  and  turbine  pumping  machinery.  The 
foremost  consideration  in  the  art  of  building  machinery  of  this  class  is 
accuracy  in  design.  Without  accuracy  in  design  it  is  not  possible 
to  secure  the  maximum  efficiencies  within  reach.  A  closely  designed 
pump  should  deliver  exactly  its  contract  number  of  gallons  against  the 
contract  pumping  head,  and  the  capacity  should  not  run  over  nor 
under.  From  a  pump  builder's  point  of  view  the  misfortune  of  falling 
short  of  the  contract  capacity  needs  no  discussion  here,  but  the  other 
misfortune  of  running  over  on  capacity  may  not  be  so  clearlyw\inder- 
stood.  One  effect  of  running  over  is  an  overload  on  the* motor, 
engine  or  steam  turbine  driving  the  pump,  and  another  result^is  that 
the  average  efficiency  of  the  equipment  in  daily  operationuis  below 
what  it  should  be,  for  ii  it  runs  over  in  capacity  its  maximum  efficiency 
does  not  occur  at  its  contract  capacity. 

2  It  will  be  noted  that  each  of  these  pumps  had  a  contract  capacity 
of  3000  gal.  per  min.,  against  a  total  head  of  308.66  Ib.  per  sq.  in. 
Table  2  of  the  paper  shows  the  performances  of  the  five  pumps  at  the 
South  Street  pumping  station.  This  table  does  not  show  the  averages, 
but  it  will  be  found  that  each  pump  averaged  approximately  3761  gal. 
per  min.  against  a  mean  total  head  of  about  313.1  Ib.  per  sq/  in. 
Although  the  head  was  about  5  Ib.  above  the  contract  condition,  the 
pumps  exceeded  the  contract  capacity  by  about  25  per  cent.  This,  no 


506  DISCUSSION 

doubt,  caused  the  motor  overload  mentioned  in  Par.  64.  The  contract 
conditions  implied  540  h.p.  actually  delivered,  and  at  the  guaran- 
teed pump  efficiency  770  b.h.p.  would  be  needed.  The  delivered 
work  under  test  was  686  h.p.,  and  according  to  the  test  efficiency  of 
72J  per  cent,  946  b.h.p.  was  used,  that  is,  approximately  23  per  cent 
excess  motor  load. 

3  There  appear  to  be  no  data  on  tests  made  on  contract  con- 
ditions. As  the  pumps  were  tested  at  a  great  excess  in  capacity  it  is 
quite  probable  that  the  efficiency  would  have  been  lowered  several 
points  if  the  pumps  had  been  throttled  to  the  agreed  capacity  and 
head.  The  tests  as  per  Table  2  show  about  686  h.  p.  delivered  and 
946  b.h.p.,  or  a  pump  loss  of  260  h.p.  For  a  considerable  range  it  is 
probably  safe  to  assume  this  260  h.p.  loss  to  be  fairly  constant. 
Assuming  this  to  be  correct  and  adding  this  loss  to  the  540  h.p. 
delivered  represented  by  the  agreed  contract  conditions,  would  give 
800  b.h.p.,  thus  showing  a  pump  efficiency  of  but  67J  per  cent.  If 
these  pumps  had  been  accurately  designed,  undoubtedly  they  would 
have  shown  as  high  efficiency  under  the  contract  conditions  as  was 
obtained  with  excess  capacity  condition. 

PROF.  E.  L.  OHLE.  There  seems  to  be  quite  a  difference  in  opinion 
among  engineers  as  to  the  reasons  for  the  variation  in  efficiency  of  the 
pumps  when  working  singly  and  in  multiple.  It  seems  to  me  that  the 
reason  is  the  one  suggested  by  Professor  Carpenter.  It  is  practically 
impossible  that  all  should  work  at  the  same  speed,  as  they  are 
independently  driven.  If  then  the  pressure  in  the  main  should  exceed 
the  pressure  which  any  pump  was  capable  of  delivering,  the  runner  of 
that  pump  would  simply  revolve  without  delivering  any  water.  This 
seems  to  be  borne  out  by  the  experience  of  one  pump  builder,  as  stated 
by  J.  J.  Brown. 

THE  AUTHOR.    The  discussion  of  the  paper  has  been  so  volum 
inous  that  there  is  really  but  little  needed  from  the  author.    In  most 
of  the  discussion  additional  information  of  value  has  been  contri- 
buted which  I  am  sure  will  be  appreciated  by  members  of  the  Society. 

2.  The  difficulties  in  connection  with  an  installation  of  the  kind 
described  in  the  paper,  involving  a  complete  system  of  piping  and 
hydrants  capable  of  withstanding  high  pressures,  as  well  as  the  nec- 
essary pumping  machinery,  are  well  brought  out.  I  think  the  gen- 
eral conclusion  will  be  that  the  piping  difficulties  to  be  overcome, 
especially  when  cast  iron  is  employed,  are  very  'serious  and  require 


HIGH-PRESSURE   FIRE-SERVICE   PUMPS  507 

special  skill  and  the  best  of  material.  Attention  has  also  been  called 
to  the  fact  that  the  city  of  Baltimore  has  adopted  a  system  in  which 
steel  pipe  is  employed  in  order  to  overcome  the  difficulties  due  to  the 
breakage  of  cast-iron  pipe. 

3  The  discussion  has  disclosed  the  construction  of  several  stations 
in  which  the  motive  power  has  been  obtained  from  gas  engines,  and 
the  advantages,  disadvantages  and  expense  of  such  installation. 

4  It  is  pointed  out  that  although  the  centrifugal  pumps  are  cap- 
able of  operation  at  the  high  efficiencies  shown  by  the  paper,  yet  at 
the  lower  heads  at  which  they  are  frequently  operated  the  efficiency 
would  be  less.    I  do  not  believe  there  is  any  serious  commercial  dis- 
advantage because  of  that  fact,  since  it  is  true  that  the  cost  of  opera- 
tion of  a  fire  station  is  principally  due  to  other -items  than  the  cost  of 
power.    A  fire  station  is  required  to  be,  above  all  things,  reliable,  and 
it  is  of  very  little  importance  whether  or  xiot  the  pumping  be  done 
under  the  most  economical  conditions  for  the  reason  that  the  total 
cost  of  pumping  is  only  a  small  portion  of  the  operating  expense. 

5  It  is  claimed  by  one  of  the  discussers  that  the  test  should  have 
been  made  by  the  city  at  the  exact  capacity  called  for  and  the  efficiency 
should  have  been  based  on  the  result  of  such  a  test.    This  doubtless 
would  have  produced  a  lower  efficiency  than  that  obtained.    In  the 
light  of  the  information  now  at  hand,  there  would  have  been  no 
injustice  in  such  a  requirement,  but  at  the  date  of  making  the  con- 
tract matters  were  different  and  such  a  requirement  would  have 
imposed  a  penalty  on  the  builders,  which  would  have  been  of  no  ad- 
vantage to  the  city.   The  reason  for  that  opinion  is,  that  at  the  time  of 
taking  the  contract  the  information  regarding  multi-stage  pumps  oper- 
ating at  high  heads  was  quice  meagre.    Mr.  Sando,  the  designer  of  the 
pumps,  secured  all  the  data  he  could  both  in  this   country  and  in 
Europe.    The  result  of  his  investigation  led  him  to  believe  that  it 
was  to  the  advantage  of  the  city  and  of  the  builders  to  put  in  a  pump 
of  such  capacity  that  it  would  surely  meet  the  requirements  in  that 
respect.     It  was  believed  that  this  would  result  in  a  considerable 
increased  capacity  over  contract  requirements.     The  motors  were 
designed  with  an  equally  liberal  capacity  so  that  the  machine  was 
intended,  even  in  the  beginning,  to  be  capable  of  a  continuous  large 
overload.    The  statement  that  the  motors  showed  any  evidence  of 
being  overloaded  is  in  error,  possibly  because  a  certain  remark  which 
I  made  was  misunderstood.    It  strikes  me  that  the  city  is  the  principal 
gainer  by  such  a  system  of  design  and  that  as  a  consequence  it  owns 
considerable  more  pumping  capacity  than  was  called  for  in  the  speci- 
fications, and  so  far  as  1  know,  without  extra  cost. 


508 


DISCUSSION 


6  1  believe  that  with  the  present  data  it  would  have  been  possible 
to  designj3othj>umps  and  motor  to  carry  25  per  cent  less  load  with 
the  same  efficiency  as  was  obtained  by  the  larger  pumps  and  motors. 
In  that  case,  a  test  at  the  specified  capacity  would  have  been  a  fair 


one. 


[The  following  curves  show  the  development  of  the  runners,  guide  wheels 
and  guide  vanes  of  the  pumps  installed  in  the  New  York  high  pressure 
pumping  stations.— EDITOR.] 


I  Developed  Cylinder  Section 
through  M-N 


Developed  Cylinder  Section 
through  X-Y 


DEVELOPMENT  OF 
SUCTION  GUIDE  VANES 


DEVELOPMENT  OF  VANES  /     j 
IN  DISCHARGE  RUNNER 


Direction  of  Itirmor 
Rotation 


DEVELOPMENT  OF 
VANES  IN  RUNNERS 


Sixteen  Blades 
'Roots  of  Blades 

at  C-D  as  — i- 

Projected  on  Plane      Direction  of 

A-B  Runner  [Rotation 


DEVELOPMENT  OF  DISCHARGE 
GUIDE  VANE 


DEVELOPMENT  Oh  VANES  IN 
STATIONARY  GUIDE  WHEELS 


510  DISCUSSION 

7  The  interesting  question  brought  out  by  these  tests  regarding 
the  higher  efficiency  obtained  with  a  single  pump  as  compared  with  all 
the  pumps  discharging  into  the  mam,  has  not  been  satisfactorily 
answered.    Such  results,  however,  seem  to  have  been  noted  by  every 
engineer  who  has  made  similar  tests. 

8  In  Par.  65  of  the  paper  I  made  one  suggestion  concerning  this 
point.     I  have  since  thought  that  the  variation  in  construction  or  in 
detailed  shape  of  the  discharge  volume  might  possibly  account  for 
some  of  these  differences.     It  is  hardly  possible  that  all  the  pumps 
can  be  made  exactly  alike  and  smal1  inherent  differences,  which 
would  be  obliterated  in  the  operation  of  all  the  pumps  together, 
might  account  for   the   higher  efficiency  of  the  pumps  operating 
singly.    As  suggested  by  Mr.  White,  the  measurements  were  of  a 
character  which  did  not  consider  the  pipe  resistances,  and  the  figures 
given  apply  to  the  delivery  from  the  pump  before  the  water  was 
subjected  to  pipe  resistances  hi  any  case. 


No.  1262 

THE   BEST   FORM   OF    LONGITUDINAL   JOINT 
FOR  BOILERS 

BY  F.  W.  DEAN,  BOSTON,  MASS. 
Member  of  the  Society 

It  has  been  generally  accepted  in  this  country  for  a  number  of 
years,  that  the  best  form  of  butted  longitudinal  riveted  joint  for 
boilers  is  that  in  which  the  inside  strap  is  wider  than  the  outside,  and 
which  has  one  or  more  rows  of  rivets  passing  through  the  shell  and  the 
inside  strap  beyond  each  edge  of  the  outside  strap.  The  pitch  of 
the  first  row  of  outer  rivets  is  double  that  of  the  rows  that  pass 
through  both  straps,  and  if  there  are  other  outer  rows  they  may  or 
may  not  have  a  still  greater  pitch. 

2  In  England;  where  until  comparatively  recently  boiler  con- 
struction has  been  superior  to  ours,  this  form  of  joint  appears  to 
receive  no  recognition.     It  was  first  devised,  as  far  as  I  know,  by 
Dr.  E.  D.  Leavitt,  Past-President  of  the  Society,  and  Edward  Kendall, 
both  of  Cambridge,  Mass.,  and  was  first  used  by  Mr.  Leavitt  in  some 
locomotive  type  boilers  designed  by  him  for  the  Calumet  &  Hecla 
Mining  Company.     I  have  a  blueprint  of  this  boiler  dated  1879.     It 
is,  of  course,  hazardous  to  state  that  this  joint  was  never  used  before 
and  it  is  quite  possible  that  it  was  used  in  England,  and  discarded  and 
forgotten  as  poor  construction,  as  I  believe  it  is.     It  was  first  used 
on  an  American  locomotive  by  the  Baldwin  Locomotive   Works  in 
a  consolidation  locomotive  built  by  them  for  the  Calumet  &  Hecla 
Mining  Company,  the  drawing  of  this  joint^havingTbeen  made  by  me 
when  I  was  in  Mr.  Leavitt's  employ. 

3  While  every  boilermaker  has  for  years  been  familiar  with  butt 
joints,  this  form  made  slow  progress  towards  adoption  in  this  country. 
One  form  of  joint  used  to  avoid  the  butt  joint  and  get  something  as 
good,  was  a  lap  joint  with  an  inside  strap  bent  at  the  edge  of  the  lap 
and  riveted  on  each  side  of  it.     This  was  used  on  locomotives  exclu- 

Presented  at  the  Annual  Meeting,  New  York,  (December  1909),   of  THE 
AMERICAN  SOCIETY  OP  MECHANICAL  ENGINEERS. 


824  LONGITUDINAL   JOINT   FOR   BOILERS 

sively,  and  was  of  little  or  no  value  as  it  was  simply  a  somewhat 
elastic  bent  tie  connecting  the  two  parts  of  the  shell  plate.  Finally, 
and  fortunately,  this  joint  gave  way  to  the  butt  joint  first  described. 

4  I  believe  there  has  been  no  case  of  an  explosion  of  a  butt-joint 
boiler;  at  least  one  due  to  rupture  of  the  joint.     Recently,  however, 
a  boiler  at  Woonsocket,  R.  I.,  narrowly  escaped  explosion,  a  longi- 
tudinal rupture  of  the  plate  on  one  side  of  the  joint,  and  within  its 
limits,  being  discovered  while  the  boiler  was  subjected  to  steam  pres- 
sure.    The  steam  pressure  was  rapidly  reduced  and  no  explosion 
occurred.     An  account  of  this  is  given  in  Power,  January  26,  1909, 
and  the  joint  itself  is  in  possession  of  the  boiler-inspection  depart- 
ment of  the  Massachusetts  district  police  at  the  state  house  in  Boston. 

5  It  has  been  growing  upon  me  for  some  years  that  a  one-sided 
boiler  joint,  such  as  that  first  described,  is  poor  construction,  and 
may  sooner  or  later  cause  a  crack  in  the  plate.     The  Woonsocket 
phenomenon  has  tended  to  confirm  this  opinion.     It  is  evident  that 
unless  the  outside  rivets  fill  the  holes  they  do  very  little  good,  and 
when  they  do  fill  them  they  form  an  overhung  connection  and  to 
some  extent  possess  in  themselves  the  now  recognized  defect  of  the 
lap  joint.     Moreover  the  extended  inside  plate  forms  a  bent  connec- 
tion between  the  different  rivets  at  different  distances  from  the  center 
line  of  the  joint. 

6  In  many  cases  designers  have  placed  the  outside  rivets  at  a 
considerable  distance  from  the  edge  of  the  outside  strap  and  this  is 
constantly  overdone.     It  is  obvious,  on  careful  thought,  that  the 
outside  rivets  should  be  as  near  the  edge  of  the  outside  strap  as  practi- 
cable, thereby  diminishing  the  bent-tie  effect.     In  order  to  diminish 
this  effect  still  further,   and   also   to  render  the    overhung   rivets 
more  effective,  the  inside  strap  should  be  thicker  than  usual,  and  this 
feature  can  hardly  be  overdone.     The  inside  strap  should  be  at  least 
as  thick  as  the  shell  plate,  and  great  care  should  be  taken  to  have 
the  holes  match  and  the  rivets  fill  the  holes. 

7  When  a  joint  of  this  kind  is  tested  to  destruction  in  a  test  ing 
machine,  it  will  be  found  to  fail  somewhat  in  detail,  the  inside  strap 
bending  slightly  and  the  outside  rivets  being  the  last  to  rupture  after 
yielding  a  little.     In  a  boiler  the  joint  would  be  weaker  than  a  flat 
specimen  on  account  of  the  bent-tie  feature.     This  could  be  pre- 
vented if  it  were  practicable  to   calk  the  inside  strap,  as  it  would 
thereby  be  compelled  to  maintain  the  circular  form.     The  theoretical 
efficiency  of  this  joint  is  greater  than  of  any  other  kind,  but  in  practice 
I  believe  the  efficiency  is  not  realized  and  the  defects  that  I  have 
described  render  the  joint,  in  my  opinion,  undesirable. 


LONGITUDINAL   JOINT   FOR   BOILERS 


825 


8  In  order  to  avoid  the  defects  of  the  one-sided  butt  joint,  I  have 
adopted  and  intend  to  use  hereafter,  a  joint  with  both  straps  of  the 
same  width,  as  illustrated  in  Fig.  1.  This  has  the  merit  of  having  all 
rivets  in  double  shear  and  the  strains  all  taken  care  of  in  the  best 
manner.  The  efficiency  of  this  joint  can  hardly  be  above  84  or  85 
per  cent  while  that  of  the  one-sided  joint  can  be  theoretically  91  or 
92  per  cent;  but  the  certainty  that  the  efficiency  of  the  former  is 
realized  in  practice  is  ample  compensation  for  the  use  of  slightly 
thicker  plates.  The  pitch  of  the  outer  rows  of  rivets  is  rather  great, 
compelling  the  use  of  a  thick  outside  strap  in  order  to  stand  calking 
and  remain  steam-tight.  I  use  an  equally  thick  inside  strap  in  order 
to  diminish  the  bent-tie  effect.  This  effect  is  small,  however,  as  the 


\ 


FIG.  1    RECOMMENDED  FORM  OF  LONGITUDINAL  JOINT 


rivets  are  all  near  the  center  of  the  joint.  It  can  be  eliminated  by 
calking  the  inside  strap,  which  is  practicable  with  this  joint,  and  is 
done  in  the  best  marine  practice.  This  assumes  that  the  calking  is 
effective  and  will  remain  so. 

9  While  this  subject  is  under  consideration,  it  is  well  to  call  atten- 
tion to  the  perfection  with  which  the  longitudinal  joints  of  boiler- 
plate cylinders  can  be  welded,  a  fact  which  has  been  demonstrated 
for  many  years  with  corrugated  furnaces  and  more  recently  with 
soda  digesters.  While  the  joints  of  corrugated  furnaces  are  in  com- 
pression those  of  digesters  are  in  tension,  and  their  proved  safety 
should  be  sufficient  to  overcome  any  timidity  concerning  the  per- 
fection and  safety  of  welded  joints.  Circumferential  joints  are  not 
so  easily  welded  as  longitudinal,  and  it  is  of  course  of  little  importance 
in  boilers  that  they  should  be  welded. 


826  DISCUSSION 

DISCUSSION 

REGINALD  P.  BOLTON.  The  form  of  longitudional  joint  for  boilers 
which  Mr.  Dean  has  described  as  the  best  is  as  old  as  the  time  of  Bru- 
nei, and  was  tested  by  him  in  1838,  and  again  by  Longridge  in  1857. 
It  is  a  double-welt  triple-riveted  joint,  omitting  alternate  rivets  in  the 
outer  strip,  and  it  has  the  defect  of  undue  distance  for  calking  between 
the  outer  rivets.  It  is  not  so  good  a  joint  as  it  would  be  when  the 
triple  riveting  is  continued,  instead  of  omitting  the  alternate  outer 
rivet.  The  other  form  of  joint  to  which  Mr.  Dean  refers,  in  which 
the  inside  welt  was  wider  than  the  outside  welt,  has  stood  the  test  of 
many  years  usage,  and  I  do  not  know  of  any  case  of  failure. 

2  In  discussing  the  longitudinal  joint,  we  should  not  lose  sight  of 
the  fact  that  the  weak  parts  of  every  longitudinal  joint  are  the  ends, 
where  the  two  shell  plates  unite  and  the  circular  seams  meet  the  longi- 
tudinal joint.  It  is  there  that  weakness  develops  in  all  joint  construc- 
tion. In  explosion  cases  on  which  I  have  been  engaged,  I  have  found 
that  trouble  has  developed  at  those  points,  and  have  noted  that  rup- 
tures commenced  there.  Therefore,  in  dealing  with  the  design  of 
longitudinal  joints,  the  essential  feature  seems  to  me  to  be  its  character 
where  it  meets  the  circumferential  seam. 

E.  D.  MEIER.  I  think  that  the  value  of  this  joint  depends  largely 
on  the  diameter  of  the  boiler  that  one  has  in  mind.  In  a  Scotch 
marine  boiler,  from  12  to  15  ft.  in  diameter,  the  joint  would  be  an 
excellent  one,  especially  with  the  scalloped  edges  mentioned  by  Mr. 
Dean1.  That  is  a  very  troublesome  thing  to  do,  but  in  addition  to  the 
advantage  of  the  scalloped  edge  which  Mr.  Dean  cited,  there  is  the 
further  one,  that  it  modifies  the  tendency,  common  to  such  joints,  to 
buckle  at  the  point  where  the  sheets  come  together.  The  butt  joint 
is  stiff er  there  than  any  other  part  of  the  shell  and  with  a  change  in  the 
pressure  and  temperature  the  buckling  ultimately  tends  to  impair  the 
joint. 

2  With  a  small  boiler,  36  in.,  42  in.,  or  48  in.  in  diameter,  the 
joint  is  too  large  a  proportion  of  the  total  circumference,  and  this 
action  would  become  worse.     That  buckling  action  is  distributed  by 
making  the  butt  plates  as  thin  as  possible,  and  making  the  inside  one 
longer  than  the  outside  one. 

3  The  welded  joint  will  be  an  ideal  one  when  we  can  be  sure  of 

i  This  was  referred  to  by  the  author  in  presenting  his  paper. 


LONGITUDINAL  JOINT  FOR  BOILERS  837 

a  weld  that  will  give  95  per  cent  efficiency.  The  difficulty  will  be  to 
test  it.  We  do  know,  however,  that  when  we  rivet  a  joint  and  do  it 
honestly,  we  have  something  that  can  be  relied  on.  Much  will  depend 
on  how  the  material  is  chosen  and  how  the  work  of  laying  up  and 
riveting  is  done.  The  joint  should  be  made  by  carefully  bending  the 
butt  straps  at  a  red  heat  to  the  true  curve,  and  rolling  the  plate  itself 
true  to  template.  This  will  make  as  perfect  a  joint  as  possible.  For 
a  large  diameter  of  boiler,  I  think  the  joint  advocated  by  Mr.  Dean, 
especially  if  the  edges  are  scalloped,  is  an  excellent  one,  but  for  smaller 
diameters  I  prefer  the  old  joint. 

4  Two  other  points  must  be  considered:  first,  how  the  calking 
is  done,  as  in  many  sheets  the  initialfracture  is  caused  by  bad  calking; 
second,  what  sort  of  metal  was  used,  for  unless  the  chemical  analysis 
of  the  plates  as  to  minimum  of  injurious  metalloids  is  firmly  insisted 
on,  trouble  is  sure  to  follow  even  in  the  best  proportioned  joints. 

PROP.  A.  M.  GREENE,  JR.  Mr.  Dean  is  probably  aware  that  in 
the  1893  report  of  the  Chief  of  the  Bureau  of  Steam  Engineering  of  the 
Navy,  it  is  shown  that^the  boilers  intended  for  the  New  York,  the 
Columbia  and  the  Minneapolis,  were  all  designed  on  the  same  plan  as 
thatjwhich  Mr.  Dean  recommends.  The  illustration  in  the  paper  is 
almost  exactly  similar  to  those  in  the  report.  These  boilers  were  all 
installed  and  have  given  entire  satisfaction. 

2  Locomotive  engineers,  however,  are  using  the  unequal  length 
butt  strap  quite  extensively.  I  know  of  locomotives  in  which  two 
rows  of  rivets  were  placed  outside  of  the  outer  butt  strap,  and  I  do  not 
know  of  any  failure  of  such  joints.  If  it  is  a  case  of  getting  increased 
efficiency,  and  still  having  the  outer  butt  strap  arranged  for  a  calking 
distance,  I  do  not  see  why  we  should  depart  from  the  method  of 
unequal  straps  to  use  the  equal  strap  arrangement  which  cannot  give 
such  high  efficiencies. 

WILLIAM  A.  JONES.  I  wish  to  point  out  the  tension  which  exists 
in  the  outer  row  of  rivets  and  its  effect  on  the  drum  shell.  This 
should  have  an  important  part  in  determining  whether  the  form  of 
joint  which  Mr.  Dean  recommends  is  really  better  than  if  the  outer 
butt  strap  were  cut  back  one  row  of  rivets  on  each  side,  so^that  the 
rivets  at  their  calking  edges  would  be  close  together.} 

2  We  probably  all  agree  that  rivets  are  more  reliable  in  shear  than 
they  are  in  tension;  that  the  more  closely  and  firmly  the  edge  of^the 
outer  butt  strap  is  held  down,  the  less  calking  will  be  required  and 


828  DISCUSSION 

the  less  possibility  there  will  be  of  injuring  the  shell  plates  by  calk- 
ing the  butt  strap  in  the  shop,  and  the  more  remote  will  be  the  prob- 
ability of  subsequent  leaks,  prompting  inexpert  men  to  calk  them 
again  later. 

3  If  we  assume  that  the  inner  rivets  are  about  3  in.  apart,  then 
the  outer  rivets  shown  in  the  joint  which  Mr.  Dean  recommends  will 
be  about  6  in.  apart,  and  each  rivet  will  be  holding  an  area  of  butt 
strap  of  from  15  to  20  sq.  in.,  which,  at  200-lb.  pressure,  will  require 
from  3000  to  4000-lb.  tension  per  rivet.     In  addition,  each  of  these 
rivets  will  be  required  to  hold  the  calking  for  an  edge  about  6  in.  long, 
and  the  calking  will  have  an  advantage  over  the  rivet  of  about  2  to  1, 
due  to  the  leverage  which  it  has  because  the  rivets  are  back  from  the 
edge.     It  does  not  require  much  thought  to  see  that  these  rivets 
would  be  better  able  to  do  this  work  if  they  were  twice  as  close  together. 

4  The  joint  which  Mr.  Dean  has  shown  has  five  rivets  in  double 
shear  on  each  side,  in  a  length  equal  to  the  pitch  of  the  outer  rivets,  so 
that  ten  times  the  area  of  one  rivet  is  the  total  area  in  shear  in  this 
length.     If,  on  the  other  hand,  the  outer  butt  strap  were  cut  back  so 
that  the  rivets  at  its  edge  would  be  close  together  and  the  outer  rivets 
were  in  single  shear,  then  the  total  area  in  shear  would  be  only  one- 
tenth  less,  and  the  proportion  of  the  circular  tension  transmitted  by 
the  rivets  in  single  shear  could  not  be  more  than  11  per  cent  of  the 
total  in  this  case. 

5  I  understand  that  it  is  in  an  effort  to  improve  the  action  of  this 
11  per  cent  of  the  force  involved  that  this  wide  outer  butt  strap  is 
recommended,  and  that  where  four  rows  of  rivets  are  used  instead  of 
six,  this  proportion  may  rise  to  20  per  cent.     In  any  case,  the  slight 
bending  in  the  shell  plate  is  less,  I  believe,  than  the  bending  tendency 
which  the  tension  would  produce  in  the  rivets,  due  to  pressure  on  the 
wide  outer  butt  strap. 

6  Let  us  consider  the  forces  acting  upon  a  rectangular  area  of 
plate  in  a  drum  shell  under  pressure.     The  circular  tensions  acting 
tangentially  at  the  edges  of  this  area  are  equal  in  intensity,  but  act  at 
an  angle  to  each  other,  so  that  each  has  a  component  normal  to  the 
chord  of  the  area  considered.     These  normal  components  exactly 
balance  the  pressure  acting  on  that  chord.     When  the  area  considered 
embraces  a  half-circle,  the  normal  components  become  equal  to  the 
circular  tension. 

7  In  the  case  of  the  outer  butt  strap,  if  all  the  circular  tensions  of 
the  drum  could  be  transmitted  to  the  outer  butt  strap  by  rivets  at  its 
extreme  edge,  the  shear  of  these  rivets  alone  would  hold  the  outer  butt 


LONGITUDINAL   JOINT   FOR   BOILERS  829 

strap  to  the  drum,  and  the  components  of  the  shears  normal  to  the 
chord  would  just  balance  the  steam  pressure  on  that  chord,  so  that  no 
tension  in  the  rivets  would  be  necessary,  except  for  calking.  Mov- 
ing the  rivets  back  from  the  edge  of  the  butt  strap  makes  the  shear 
act  more  nearly  parallel  to  the  chord,  while  it  does  not  diminish  the 
chord,  so  that  shear  alone  will  no  longer  hold  the  butt  strap  in  place, 
and  tension  must  be  developed  in  the  rivets  to  make  up  the  difference. 

8  Transmitting  part  of  the  circular  tension  through  the  inside  butt 
strap  further  increases  the  tension  on  the  rivets,  due  to  pressure,  but 
the  additional  tension  in  this  case  maintains  the  curve  in  the  inner 
butt  strap  by  stitching  it  to  the  surface  which  receives  the  pressure, 
and  the  reaction  of  the  tension  at  the  inner  ends  of  these  rivets  is  thus 
provided  for. 

9  In  the  case  of  the  outer  rivets  of  the  joint  which  Mr.  Dean  shows, 
reaction  of  this  tension  at  the  inner  ends  of  the  rivets  must  be  absorbed 
by  an  abrupt  change  in  direction  of  the  circular  tension  at  those 
points,  tending  to  produce  corners  in  the  drum  shell  in  order  to  satisfy 
the  triangle  of  the  three  forces  formed  by  the  tension  on  the  rivet,  the 
tangential  tension  to  the  right,  and  the  tangential  tension  to  the  left. 
If  we  assume  a  42-in.  drum,  200-lb.  steam  pressure,  6-in.  pitch  of  outer 
rivets,  each  of  which  takes  in  tension  the  pressure  of  20  sq.  in.,  we  have 
4000-lb.  tension  in  each  rivet  due  to  steam  pressure,  the  inner  ends  of 
the  rivets  being  anchored  by  an  abrupt  change  in  direction  of  about  9 
deg.  of  25,200-lb.  circular  tension. 

10  Evidently,  this  abrupt  change  of  direction  of  the  total  circular 
tension  may  readily  distress  the  plate  more  in  the  form  of  joint  which 
Mr.  Dean  recommends  than  in  the  usual  form  of  joint  with  the  narrow 
outer  butt  strap,  even  though  a  very  small  part  of  the  circular  tension 
is  transmitted  through  a  rivet  in  single  shear. 

11  Mr.  Dean's  statement  that  he  believes  there  has  been  no  case 
of  failure  of  butt-strap  joints,  would  indicate  that  there  was  nothing 
wrong  with  the  established  form  using  the  narrow  outer  butt  strap. 
Certainly  the  remedy  proposed  seems  more  objectionable  than  a  rivet 
in  single  shear. 

SHERWOOD  F.  JETER/  It  seems  that  all  engineers  design  joints 
with  reference  to  their  weakest  point,  that  is,  provided  the  joint  were 
to  be  ruptured  in  a  machine.  Of  all  the  explosions  that  to  my  knowl- 
edge have  been  due  to  ruptures,  none  have  occurred  in  the  theo- 

1  The  Bigelow  Co.,  New  Haven,  Conn. 


830  DISCUSSION 

retically  weakest  part  of  the  joint.  Most  explosions  due  to  rupture 
of  the  sheet  have  occurred  near  the  joint  and  were  apparently  due  to 
flexure  of  the  metal,  which  had  destroyed  its  life  at  the  particular 
point  of  rupture. 

2  I  believe  that  there  is  a  great  need  for  an  investigation  as  to 
what  causes  the  rupture  of  the  plate,  and  for  other  than  machine  tests 
of  different  kinds  of  joints.  An  account  in  Power  states  that  there 
have  been  four  ruptures  of  butt-strap  joints  of  a  nature  similar  to  what 
was  previously  alluded  to  as  a  "lap  cracking"  of  the  joint.  From  the 
great  number  of  lap  joints  in  successful  use  for  twenty-five  years  or 
more,  it  may  be  judged  that  something  besides  a  mere  lapping  of  the 
plates  causes  such  defects. 

THE  AUTHOR.  There  is  very  little  for  me  to  say  in  closing,  as 
my  views  have  been  fully  set  forth  in  the  paper.  I  am  interested  in 
the  history  of  this  joint  as  stated  by  Mr.  Bolton.  I  first  knew  of 
it  in  1889;  it  is  shown  in  Thomas  W.  TrailFs  book  on  Boilers,  and  a 
table  of  sizes  of  parts  is  there  given. 

2  Several  of  the  speakers  express  doubt  as  to  the  tightness  of 
the  joint  on  account  of  the  wide  spacing  of  the  outer  row  of  rivets. 
There  should  bejio^doubt  of  this  kind,  for  too  many  of  them  are  in 
use.  I  know  of  one  joint  with  li-in.  rivets  [in  1-in.;  straps  on^  a 
pitch  of  9J  in.,  and  another  with  1  A-in.  rivets  inVj-m-  strap  on  a 
pitch  of  8|  in. 


No.    1329 

STRAIN  MEASUREMENTS  OF  SOME  STEAM 
BOILERS    UNDER    HYDROSTATIC    PRESSURE 

BY  JAMES  E.  HOWARD;I  WASHINGTON,  D.  C. 

Non-Member 

The  object  of  these  tests  is  to  ascertain  the  condition  of  the  metal 
of  the  shell  and  other  parts  of  two  horizontal  tubular  steam  boilers 
which  had  been  in  use  for  a  term  of  service  of  unusual  length;  and  in 
addition  thereto  to  acquire  information  on  constructive  details  by 
means  of  measured  strains. 

2  The  boilers  were  contributed  for  investigative  purposes  by 
the  treasurer  of  the  Kendall  Manufacturing  Company,  Providence, 
R.  I.,  the  late  Nicholas  Sheldon,  Esq.     They  were  of  early  manufac- 
ture and  from  their  remarkable  history  and  present  condition  were 
of  special  value  for  these  tests.     They,  were  made  by  the  Whittier 
Machine  Company,  Boston,  Mass.,  using  "Benzon"  brand  of  steel, 
and  were  put  into  service  March  1881.     They  were  in  continuous 
service  for  a  period  of  27  years,  during  which  time,  as  Mr.  Sheldon 
wrote,  "no  repairs  were  required;  in  fact,  not  one  cent  has  been  spent 
upon  them." 

3  They  consisted  of  five  course  boilers,  two  sheets  to  a  course, 
having  the  following  general  dimensions: 

Diameter,  in 72 

Length  over  dry  sheet,  ft 16 

Thickness  of  shell,  in I 

Thickness  of  heads,  in 2 

Number  of  tubes 140 

Diameter  of  tubes,  in 3 

Length  of  tubes,  ft 15 

Diameter  of  dome,  ft 2$ 

Longitudinal  seams,  double-riveted  lap  joints,  f-in.  rivets,  2-in.  pitch,  punched 

holes,  rows  2£  in.  apart,  rivets  staggered. 
Girth  seam,  f-in.  rivets,  2J-in.  pitch. 
Heads  stayed,  each,  with  14  braces. 
Cast-iron  manhole  frames  and  safety-valve  nozzle. 
Supported  by  lugs,  three  on  a  side. 
The  feedwater  came  from  the  Pawtucket  River. 

1  Engineer-Physicist,  Bureau  of  Standards,  Washington,  D.  C. 

Presented  at  the  Annual  Meeting  1911,  of  THE  AMERICAN  SOCIETY  OF  ME- 
CHANICAL ENGINEERS. 

639 


640  STRAIN   MEASUREMENTS   OF   STEAM   BOILERS 

4  The  hydrostatic  tests  were  made  at  the  W.  H.  Hick's  Boiler 
Works,  Providence.     Mr.  Francis  B.  Allen,   Vice-President  of   the 
Hartford  Steam  Boiler  Inspection  &  Insurance  Company,  assisted 
and  advised  with  the  writer  in  conducting  them.     The  boilers  will 
be  designated  by  the  numbers  4084  and  4092  under  which  they  were 
carried  on  the  books  of  the  Hartford  company. 

5  The   tests   began   with   strain   measurements   upon  different 
parts  of  the  boilers  as  they  were  subjected  to  successive  increments 
of  hydrostatic  pressures.     The  results  of  this  portion  of  the  inquiry 
are  now  available  and  herewith  presented.     Much  remains  to  be 
done  in  the  other  direction  of  testing,  pertaining  to  the  physical 
properties  of  the  materials. 

6  Measurements  of  the  deformations  of  engineering  structures, 
whether  steam  boilers,  bridges  or  buildings,  may  be  expected  to  de- 
velop information  of  a  kind  not  attainable  in  the  tests  of  the  com- 
ponent parts   of  those   structures.     A   comparatively  new   field  of 
inquiry  is  presented  in  the  tests  of  structures  over  the  tests  of  the 
materials   thereof.     The   effects   of   combined   stresses  may  readily 
be  studied  in  this  manner. 

7  No  more  simple  type  of  boiler  could  be  chosen  than  the  plain 
horizontal,  tubular  boiler  of  these  tests,  yet  it  will  be  seen  from  the 
results  that  complexity  of  strains  and  stresses  are  found  in  most 
parts    of   the    shell.     In    comparatively   few    places    are  tangential 
strains  displayed  corresponding  in  magnitude  to  those  which  would 
be  expected  in  a  thin  cylindrical  shell  subjected  to  a  given  interior 
pressure. 

8  Ascertaining  the  deformations  by  the  method  of  measured 
strains,  locally  determined,  consists  of  establishing  gaged  lengths  on 
different  parts  of  the  boiler  and  then  measuring  them  initially  and  at 
intervals  as  the  hydrostatic  pressures  are  successively  applied  and 
released. 

9  Gaged  lengths  of  10  in.  each  were  used  in  the  examination  of 
these  boilers.     Their  extremities  were  defined  by  small  drilled  and 
reamed  holes.     The  holes  are  about  0.05  in.  in  diameter  by,  say,  0.10 
in.  deep,  and  reamed  to  a  conical  shape.    The  angle  of  the  reamer 
is  65  deg.,  and  the  distance  across  the  hole  at  the  surface  of  the  shell 
sheet  about  0.08  in. 

10  Such  holes  carefully  made,  in  metal  surfaces,  are  capable  of 
centering  with  considerable  precision  the  contact  points  of  the  mi- 
crometer strain  gage.  The  strain  gage  is  used  as  a  transfer  instrument 
to  compare  the  gaged  lengths  on  the  work  with  a  corresponding  length 
on  a  standard  reference  bar. 


JAMES   E.   HOWARD  641 

11  Fig.  1  shows  the  10-in.  strain  gage  used  on  these  tests.     It 
consists  of  two  principal  parts,  an  outer  tube  and  an  inner  stem,  which 
are  telescopic,  working  on  ball  bearings.     Each  part  carries  a  coni- 
cal contact  point  for  centering  the  instrument  on  the  reference  bar 
and  on  the  work.    A  screw  micrometer  measures  the  length  of  the 
instrument  when  in  position. 

12  The  conical  contact  points  of  the  strain  gage  have  an  angle  of 
55  deg.    This  difference  of  10  deg.  between  the  reamed  hole  in  the 
boiler  shell  and  the  points  of  the  gage  secures  contact  at  a  short  dis- 
tance below  the  surface  of  the  shell.     Ordinarily  the  reference  holes 
are  safe  against  accidental  injury,  due  to  their  position. 

13  As  to  the  degree  of  precision  attained  with  the  strain  gage,  in 
the  hands  of  skilled  manipulators  and  under  favorable  conditions, 
such  as  were  experienced  with  these  boilers,  it  is  believed  the  readings 
are  generally  reliable  to  one  ten-thousandth  of  an  inch.     This  strain 
corresponds  to  a  stress  of  300  Ib.  per  sq.  in.  on  a  10-in.  gaged  length, 


FIG.  1    10-lN.  STRAIN  GAGE 

using  a  modulus  of  elasticity  of  30,000,000  Ib.  Fig.  2  shows  boiler 
No.  4084.  Both  boilers  were  of  the  same  dimensions  except  at  the 
dry  sheets.  When  on  their  settings,  boiler  No.  4084  was  on  the 
right,  boiler  No.  4092  on  the  left  side.  This  view  shows  the  locations 
of  some  of  the  gaged  lengths  which  were  established  on  this  boiler, 
taken  in  both  tangential  and  longitudinal  directions. 

14  A  more  comprehensive  series  of  lengths  was  established  on 
boiler  No.  4092,  and  the  general  discussion  of  the  results  of  the  strain 
measurements  will  be  given  in  connection  with  the  test  of  that  boiler. 

15  In  the  test  of  No.  4084  greater  strains  were  displayed  in  the 
vicinity  of  the  dome  and  the  manhole  frame  than  at  other  parts  of 
the  shell.     This  resulted,  as  would  clearly  be  expected,  in  the  early 
failure  of  the  boiler  at  those  places. 

16  Actual  rupture  of  the  dome  was  not  accomplished,  but  leakage 
along  its  single-riveted  longitudinal  seam  became  so  great  at  266  Ib. 
pressure  that  it  was  necessary  to  remove  the  dome  and  patch  the 
shell  in  order  to  reach  higher  pressures  with  the  pump  available. 


642 


STRAIN   MEASUREMENTS   OF   STEAM   BOILERS 


H 

i 

H 
PQ 


JAMES   E.    HOWARD 


643 


cast-iron   manhole   frame  fractured 
Another  patch  was  then  put  on  the 


17  At  270  Ib.  pressure  the 
across  the  middle  of  its  length. 
shell  covering  the  manhole. 

18  The  test  was  again  resumed  when  at  295  Ib.  pressure  the  rupture 
of  three  braces  of  the  front  head  occurred.     The  test  was  then  dis- 
continued and  the  boiler  dismantled. 


FIG.  3     INTERIOR  OF  DOME  SHOWING  LINES  ALONG  WHICH  SCALE  WAS  DIS- 
TURBED AFTER  PRESSURE  OF  266  LB.  ON  SHELL 

19  The  strain  measurements  made  in  the  test  of  No.  4084  were 
of  the  same  general  order  as  those  subsequently  made  in  the  test  of 

.the  second  boiler  and  the  results  were,  for  the  most  part,  quite  similar. 

20  A  feature,  however,  in  the  test  of  the  first  was  absent  or  obscure 

TABLE  1     TANGENTIAL  EXTENSIONS  OF  THE  SEAMS,  BOILER  NO.  4084 


Course 


.Treasures 

B 

C 

D 

E 

210 

0.0166 

0.0121 

0.0099 

0.0084 

240 

0.0241 

0.0171 

0.0138 

0.0121 

270          0.0341          0.0241 

0.0212 

0.0187 

in  that  of  the  second.  There  was  a  progressive  difference  in  the  exten- 
sibility taken  across  the  longitudinal  seams  of  the  several  courses 
in  passing  from  the  front  to  the  rear  end  of  the  boiler. 

21     The  tangential  extensions  of  the  seams,  at  the  middle  of  their 
lengths,  were  as  shown  in  Table  1. 


644 


STRAIN   MEASUREMENTS   OF   STEAM   BOILERS 


22  While  these  seams  were  not  directly  exposed  to  the  heated  gases 
over  the  grate,  nevertheless  it  seems  probable  that  a  wider  range  of 
thermal  conditions  prevailed  in  the  vicinity  of  the  seams  at  the  front 
end  over  those  at  the  rear  end  of  the  boiler.  If  such  was  the  case  it 
would  aid  in  explaining  the  greater  slip  of  the  forward  seams. 


FIG.  4 


INTERIOR  VIEW  OF  BOILER  No.  4084  AFTER  295  LB.  PRESSURE  SHOWING 
SCALE  DISTURBED  IN  VICINITY  OF  THE  LONGITUDINAL  SEAMS 


23  Hydrostatic  pressures  on  the  exterior  surfaces  of  the  tubes 
necessarily  extend  them  in  length.     The  amount  of  the  extension 
appears  to  depend  upon  their  position  with  reference  to  their  proxim- 
ity to  the  shell.     Tubes  adjacent  to  the  shell  extended  less  than  those 
at  the  middle  of  the  rows,  a  restraining  influence  from  the  shell  appear- 
ing to  affect  the  outer  ones. 

24  The  results  in  Table  2  were  obtained  by  measuring  the  tubes 
over  their  full  length. 

25  Practically  no  leakage  occurred  about  the  tubes  throughout 
the  test  of  this  boiler.     A  slight  leakage  took  place  at  two  tubes  at 
120  Ib.  pressure,  but  soon  ceased  and  was  not  renewed  during  the 
remainder  of  the  test.     The  girth  seams  remained  tight  up  to  210 
Ib.  pressure,  and  then  showed  only  small  leaks  which  were  not  mate- 
rially increased  under  the  higher  pressures. 

26  Leakage  at  the  longitudinal  seams  began  at  120  Ib.  pressure 
and  increased  as  higher  pressures  were  applied.     The  leakage  became 
general  at  these  seams  with  180  Ib.  pressure  on  the  boiler,  but  at 


JAMES  E.    HOWARD 


645 


this  time  the  slip  of  the  joints  had  become  a  pronounced  feature  of 
the  case,  which  necessarily  disturbed  the  calking. 

TABLE  2    EXTENSION  OF  TUBES,  BOILER  NO.  4084 


THIRD  Row 

SEVENTH  Row 

Next  Shell 

Middle  of  Row 

Next  Shell 

Middle  of  Row 

210 

0.0110 

0.0162 

0.0077 

0.0167 

240 

0.0128 

0.0184 

0.0086 

0.0189 

270 

0.0142 

0.0210 

0.0099 

0.0210 

•  27  Upon  removal  of  the  dome,  evidence  of  overstraining  was 
found  at  its  base  next  the  flanged  portion.  The  scale  had  been  dis- 
turbed on  the  inside  on  the  line  and  in  the  vicinity  of  the  upper 
element  of  the  boiler,  as  shown  in  Fig.  3.  Near  the  flange  the  scale 
was  disturbed  in  oblique,  shearing  directions,  which  changed  to  longi- 
tudinal and  then  tangential  directions  a  little  farther  up  the  dome. 


FIG.  5  INTERIOR  VIEW  OF  BOILER  No.  4084  AFTER  295  LB.  PRESSURE 
SHOWING  SCALE  DISTURBED  IN  VICINITY  OF  THE  LONGITUDINAL  SEAM  AND 
UNDER  SUPPORTING  LUG 

28  Figs.  4  and  5  are  interior  views  of  the  boiler  illustrating  the 
manner  in  which  the  scale  was  disturbed  during  the  test  in'the  vicin- 
ity of  the  longitudinal  seams  and  under  one  of  the  lugs. 

29  Struts  were  used  under  the  middle  lugs  and  supported  a  part 
of  the  weight  of  the  boiler  during  the  test.     They  probably  intensi- 


646  STBAIN  MEASUREMENTS   OF  STEAM  BOILERS 

fied  the  stresses  in  the  shell  in  that  vicinity.  The  interior  surface  of 
the  shell  and  also  the  heads  were  found  in  good  condition.  Fig.  6 
shows  the  appearance  of  the  inside  of  the  rear  head. 

30  A  series  of  six  photographs,  Figs.  7  to  12  inclusive,  shows  the 
appearance  of  the  exterior  surfaces  of  the  tubes.    The  system  of  let- 
tering and  numbering  the  horizontal  and  the  vertical  rows  is  indi- 
cated in  Fig.  6.     The  layout  of  the  feed  pipes  appears  on  Fig.  13. 

31  Tubes  in  the  horizontal  row  marked  D,  the  fourth  in  the  boiler 
from  the  top,  Fig.  7,  had  a  deposit  on  the  rear  third  of  their  length, 
and  also  a  slight  deposit  on  the  front  ends.     On  some  of  the  lower 
rows  the  deposit  was  thicker,  as  Figs.  8-12  indicate.     In   general 
the  deposit  was  greatest  in  the  lower  rows  of  tubes  and  on  those  far- 
thest from  the  shell,  being  confined  chiefly  to  the  rear  quarter  or 
half  of  their  lengths.     The  lower  rows  of  tubes,  at  the  front  end  of 
the  boiler,  had  a  deposit  on  them.    The  surfaces  of  the  upper  row 
and  the  side  rows  were  clean  without  deposit. 

32  Material  collected  from  the  bottom  of  the  boiler  at  the  front 
and  rear  ends  had  the  following  approximate  chemical  composition: 

Deposit  from  front  end  of  .boiler:  Per  Cent 

Loss  on  ignition 26.00 

80s 4.10 

Silica 21 . 60 

Fe208+Al203 25.40 

Lime 5.30 

Magnesia 13 . 10 

Copper  oxide  (about) 0.25 

CO2 slight  amount 

Chlorides trace 

Deposit  from  rear  end  of  boiler :  Per  Cent 

Loss  on  ignition 23 .85 

S08. trace 

Silica 27.60 

Fe80,-f  Al,08 24 . 80 

Lime 9.60 

Magnesia 12.70 

Copper  oxide  (about) 0.25 

Chlorides trace 

Carbonates small  amount 

33  Prior  to  testing  boiler  No.  4092,  it  was  stripped  of  its  dome  and 
manhole  frame  and  the  shell  patched  at  those  places.     The  heads 
were  strengthened  by  means  of  six  1  J-in.  braces  extending  from  head 


JAMES   E.    HOWARD 


647 


to  head.  The  cast-iron  safety-valve  nozzle  was  allowed  to  remain 
in  place,  but  was  eventually  replaced  by  a  soft  patch,  after  300  Ib. 
pressure  had  been  applied  and  released.  The  distortion  of  the  shell 
under  the  flange  of  the  nozzle  caused  leaks  impracticable  to  calk. 

34  Fig.  14  shows  the  boiler  when  about  ready  for  the  hydrostatic 
test.     It  was  supported  on  two  wooden  shoes  sawed  to  fit  the  curva- 
ture of  the  shell,  in  lieu  of  the  blocking  shown  in  the  illustration. 

35  The  gaged  lengths  which  were  established  on  the  right  side 


FIG.  6  INSIDE  OF  REAR  HEAD,  BOILER  No.  4084,  AFTER  295  LB.  PRESSURE. 
LETTERS  AND  FIGURES  REFER  TO  MARKS  SHOWING  LOCATION  OF  TUBES  IN  SUB- 
SEQUENT PHOTOGRAPHS 

of  the  boiler  are  shown  in  this  figure  and  practically  stand  for  those 
on  the  left  side,  while  additional  ones  were  laid  off  on  the  top.  Figs. 
15,  16  and  17  show,  however,  the  different  gaged  length  on  each  side 
and  the  top.  Additional  gaged  lengths  were  laid  off  and  measured 
which  are  not  shown  on  these  diagrams;  their  results  confirm  those 
which  will  be  referred  to.  There  were  165  gaged  lengths  used  in  the 
principal  series  of  observations,  on  which  some  3300  readings  were 
taken. 

36  The  general  results  of  the  strain  measurements  have  been 
plotted  on  a  series  of  ten  diagrams,  Figs.  18  to  27,  inclusive.  For  the 


648 


STRAIN   MEASUREMENTS   OF  STEAM   BOILERS 


JAMES   E.   HOWARD 


649 


650 


STRAIN    MEASUREMENTS    OF   STEAM    BOILERS 


II 


s 

M  tf 

P  W 

«  O 

W  PQ 

5  O 

$  S 

Q  co 


.1 


JAMES  E.   HOWARD 


651 


purpose  of  furnishing  a  convenient  basis  of  comparison,  in  judging 
the  behavior  of  the  boiler  at  different  parts  and  under  different 
pressures,  heavy  lines  have  been  drawn  on  each  diagram  which  indi- 
cate strains  corresponding  to  those  which  would  be  displayed  by  the 


^/^^ 

? 
0 

^ 

i 

c 

N 
\ 

) 

« 

-j.           i 

r 
>i                                              rr, 

**  * 

1                      M.           ttr^ 
i                ? 

/  _  /  * 

FIG.  13    LAYOUT  OP  FEED-PIPES 
Pipe  A    Discharged  directly  over  Tubes  of  Row  No.  5  at  Rear  End 
Pipe  B    Discharged  directly  over  Tubes  of  Row  No.  12  at  Front  End 

TABLE  3    COMPUTED  STRESSES  ON  THE  SHELL  SHEETS,  BOILER  NO.  4092 


Boiler  Pressure,  Lb. 
per  Sq.  In. 

Stress  on  Mn.  Shell,  Lb. 
pex  Sq.  In. 

Strain  on  Gaged  Length 
of  10  In. 

30 

2880 

0.0010 

60 

5760 

0.0019 

00 

8640 

0.0029 

120 

11520 

0.0038 

150 

14400 

0.0048 

180 

17280 

0.0058 

210 

20160 

0.0067 

240 

23040 

00077 

270 

25920 

0.0086 

300 

28800 

0.0096 

sheets  under  direct  tensile  stresses,  using  a  modulus  of  elasticity 
of  30,000,000  Ib.  per  sq.  in.  Plotted  curves,  which  are  steeper  than 
the  modulus  of  elasticity  reference  line,  indicate  places  on  the  boiler 
having  greater  rigidity  than  normal  to  the  plain  sheets;  while  natter 
curves  indicate  greater  extensibility  than  pertains  to  the  plain  metal. 
37  Tangential  rigidity  above  the  normal  was  displayed  in  the 
vicinity  of  the  girth  seams,  while  the  gaged  lengths  taken  across  the 
longitudinal  seams  at  the  middle  of  the  length  of  the  courses  showed 
a  much  lower  degree  of  rigidity  than  common  to  the  plain  sheet. 
Zones  of  greater  extension  than  normal  were  also  found  in  the  vicinity 
of  the  manhole  and  dome. 


652 


STRAIN   MEASUREMENTS   OF   STEAM   BOILERS 


JAMES   E.    HOWARD 


653 


38  Flattening  of  the  curves  representing  the  solid  sheets  neces- 
sarily accompanied  those  pressures  which  caused  a  tensile  stress  on 
the  shell  in  excess  of  its  elastic  limit. 

39  Table  3  shows  the  computed  stresses  on  the  shell  sheets,  con- 
sidering only  tangential  stresses  as  acting,  and  the  strains  which  should 


FIG.  15    DIAGRAM  SHOWING  LOCATION  OF  GAGED  LENGTHS,  10  IN.  EACH, 
LAID  OFF  ON  RIGHT  SIDE  ON  BOILER  No.  4092 


FIG.  16    DIAGRAM   SHOWING   LOCATION   OF   GAGED   LENGTHS,    10  IN.    EACH, 
LAID  OFF  ON  LEFT  SIDE  OF  BOILER  No.  4092 


be  developed  on  a  gaged  length  of  10  in.,  using  a  modulus  of  elastic- 
ity of  30,000,000  lb.,  the  interior  diameter  of  the  boiler  being  72  in. 
40     Referring  now  to  the  plotted  results,  Fig.  18  shows  the  tan- 
gential extensions  of  sheets  C  and  D  on  the  right  and  left  sides  of  the 


654 


STRAIN   MEASUREMENTS   OF   STEAM   BOILERS 


boiler  respectively,  taken  at  the  middle  of  the  lengths  of  the  courses. 
Gaged  length  D-18,  on  the  right  side  of  the  boiler,  was  located  above 
the  longitudinal  seam,  while  C-16,  on  the  right  side,  was  located  below 
the  longitudinal  seam. 

41  The  tangential  extensions  of  each  of  these  gaged  lengths  closely 
follow  the  modulus  of  elasticity  comparison  curve.  The  departure 
of  Z)-18  from  this  line  does  not  exceed  0.0002  in.  at  any  pressure,  and 
coincides  with  it  at  several  pressures.  The  extensions  displayed  by 
the  gaged  lengths  on  the  opposite  side  of  the  boiler  agreed  fairly  well 


FIG.  17    DIAGRAM   SHOWING  LOCATION  OF  GAGED   LENGTHS,   10  IN.   EACH, 
LAID  OFF  ON  TOP  OF  BOILER  No.  4092 


with  the  modulus  of  elasticity  reference  line  also,  but  not  so  closely 
as  the  results  found  on  the  right  side,  while  rapid  extension  took 
place  one  increment  of  pressure  earlier  than  on  the  right  side.  So 
close  a  correspondence  between  the  measured  and  the  computed 
strains  as  shown  on  this  diagram  did  not,  however,  characterize  many 
places  on  the  shell.  Commonly  there  were  modifying  influences  which 
disturbed  the  normal  display  of  elastic  extensions  of  the  metal. 

42  Fig.  19  shows  that  the  tangential  strains  near  the  girth  seams, 
D-5  and  Z>-9,  were  less  than  at  the  middle  of  the  course.     In  general 
this   behavior  was   shown   in   the  other  courses,  but  an  exception 
was  found  on  the  left  side  of  the  boiler  in  course  B  where  substan- 
tially the  same  rigidity  was  displayed  at  the  middle  as  at  the  edges 
of  the  course. 

43  In  the  third  group  of  curves  on  this  diagram,  however,  the  ex- 
tension of  D-16  taken  at  the  middle  of  the  course  is  seen  to  be 
greater  than  at  D-8  and  D-12,  curves  representing  the  edges. 

44  There  is  a  marked  difference  in  the  tangential  extension  of  the 
two  edges  of  the  end  courses  of  the  boiler,  due  to  the  influence  of  the 


JAMES   E.   HOWARD 


655 


heads  in  supporting  the  shells.  Fig.  20  shows  the  greater  rigidity  of 
gaged  lengths  #-12  which  are  taken  nearly  over  the  rear  head,  than 
at  the  other  places,  which  were  measured  on  this  course. 


-f 


20          30          4O 


40        so        so        70        eo        90    .0100       no 

O       .0010  go         3O          4O  SO          OO  7C         SO 


JOIOO          IIO          I2O 


FIG.   18    CURVES  OF  TANGENTIAL  EXTENSION,  SOLID  SHEETS,  AT  MIDDLE 
OF  LENGTH  OF  COURSES  C  AND  D,  RIGHT  AND  LEFT  SIDES  OF  BOILER 


/ /  t-30,000.<.VX)f/ 

os6  y/o  ad  i         foiai  9 


000,Q10/ 

2^^^ 


r 

S   /M 


O   HO 
*     a. 


7 


^^ 


.00/0  20  30  40 


SO  K>  70          SO  90      MOO 

JOOIQ        20       x       -to       so       eg        ro       eo       ao   .0/00      no      120 

0        .0010  20          JO          40  SO          60  70          8O  00     . 


.OOIO 

STRAINS  IN  INCHES 


FIG.  19    CURVES  OF  TANGENTIAL  EXTENSION,  SOLID  SHEETS,  NEAR  GIRTH 
SEAMS  AND  AT  MIDDLE  OF  LENGTHS  OF  COURSES 


45    In  regard  to  the  top  of  the  boiler  there  were  many  disturbing 
factors  present,  as  indicated  by  Fig.  21.     The  first  course  is  a  short 


656 


STRAIN   MEASUREMENTS   OF   STEAM   BOILERS 


one  with  the  front  head  to  stiffen  one  edge.     Then  came  the  dome  in 
the  original  construction  on  course  B,  which  was  patched,  and  the 


FIG.  20    CURVES  OF  TANGENTIAL  EXTENSION,  SOLID  SHEETS,  END  COURSE 
E,  NEAR  REAR  HEAD,  GIRTH  SEAM,  AND  MIDDLE  OF  LENGTH  OF  COURSE 


I 

<o  /SO 


0010          20  30 


40  SO  60 

o      .00/0       20       30 


eo       so    .0/00  i/o 

SO           60  70 

.00/0          20  3O 

'5  IN  INCHES 


A-30,000,OOC 


FIG.  21  CURVES  OF  TANGENTIAL  EXTENSION,  TOP  OF  BOILER,  NEAR  FRONT 
HEAD,  GIRTH  SEAMS,  DOME  AND  MANHOLE  PATCHES,  AND  SAFETY-VALVE 
NOZZLE 

patch  double-riveted,  using  the  rivet  holes  that  were  made  for  secur- 
ing the  flange  of  the  dome  to  the  shell.     Course  C  had  the  manhole 


JAMES   E.    HOWARD 


657 


patch,  a  single  riveted  one,  using  the  holes  made  for  securing  the 
manhole  frame  to  the  shell.     In  course  D  was  found  the  feed  water 


0       .OO/O  2O          3O          4O          SO  60  70          SO  90      .OIOO         I/O          I2O         /3O         MO         ISO         I6O          17O        ISO 


6O  6O  7O          60  9O      .0100         HO          120         /JO         MO 


FIG.  22  CURVES  OF  TANGENTIAL  EXTENSION,  ACROSS  LONGITUDINAL  SEAMS, 
AT  MIDDLE  OF  LENGTH  OF  COURSE  C,  AND  AT  EDGES,  RIGHT  AND  LEFT  SIDES 
OF  BOILER 


300r- 


& 


60        70        ao       90    .0100       no       120       tjo       140      iso       no       /TO loo 

ZO  JO          40          JO          60  70          00  90     .0/00         IIC         120         130         I4O 

STRAINS  IN  INCHES 


FIG.  23  CURVES  OF  TANGENTIAL  EXTENSION,  ACROSS  LONGITUDINAL  SEAMS, 
AT  MIDDLE  OF  LENGTH  OF  COURSE  D,  AND  AT  EDGES,  RIGHT  AND  LEFT 
SIDES  OF  BOILER 

connection  which  probably  did  not  have  much  influence  on  the  behav- 
ior of  this  course  while  under  pressure.     Course  E  had  the  cast-iron 


658 


STRAIN   MEASUREMENTS   OF   STEAM   BOILERS 


safety-valve  nozzle  riveted  to  it,  which  did  seem  to  have  an  influence 
on  the  tangential  extension  of  the  steel,  permitting  greater  extension 
than  normal. 


7F 


t-J 


Hf 


eo        so     .0100 
STRAINS  IN  INCHES 


ZO          /JO         MO          ISO          I6O          I7O 


FIG.  24    CURVES  OP  TANGENTIAL  EXTENSION,  ACROSS  LONGITUDINAL  SEAMS 
AND  SOLID  SHEETS,  END  COURSE  A\  EXTENSIONS  NEAR  FRONT  AND  GIRTH 

SEAM 


ooa.oop 
ci 


c-.  0,000,000 
-£T*~ 


"T 


ISO 


I 

u  /so 

5 

8   120 


0        .0010  20 


S  TRAINS  IN  INCHES 

FIG.  25  CURVES  OP  TANGENTIAL  EXTENSION,  ACROSS  LONGITUDINAL  SEAMS, 
END  COURSE  E,  EXTENSIONS  NEAR  REAR  HEAD  AND  GIRTH  SEAM  AND 
MIDDLE  OF  LENGTH  OP  COURSE 

46  The  extension  of  course  A  at  the  edge  over  the  front  head  was 
less  than  at  the  opposite  edge.  Gaged  lengths  £-52  and  £-57  showed 


JAMBS  E.  HOWARD 


659 


the  influence  of  the  overlapping  metal  of  the  patch,  as  well  as  that  of 
the  girth  seams.  The  extension  at  these  two  places  was  less  than 
normal. 


°0       ICO/0  20          30  40          55          TO 70 SO          OO    .OlOO        770 7*0 130        I4O liO          'to         I7O         lao 

STRAINS  IN  INCHES 

FIG.  26  CURVE  OP  TANGENTIAL  RESILIENCE,  ACROSS  LONGITUDINAL  SEAM, 
COURSE  D,  RIGHT  SIDE  OP  BOILER,  AT  MIDDLE  OF  COURSE  AND  NEAR  GIRTH 
SEAMS 


0         .000-  30  30          40          SO  id  TV          6O 9O lotod          I/O         I2O          130         I4O 


30         160          I  TO        160 

no       i 20       1 30      140 


0         .00/0  tO  3O          40          30  SO  TO  60  90      .0100 


FIG.  27    CURVES  OP  TANGENTIAL  EXTENSION,  HAND-RIVETED  SECTION, 
COURSE  C,  TOP  OP  BOILER 

47  At  the  side  of  the  manhole  patch,  (7-58,  there  was  found  dimin- 
ished rigidity  in  the  shell.  The  weakness  of  this  single-riveted  patch 
was  apparent  in  the  measurements  from  the  earliest  pressures  which 


660 


STRAIN   MEASUREMENTS   OF   STEAM   BOILERS 


were  applied  to  the  boiler.  Conditions  about  the  safety-valve  nozzle 
did  not  seem  fully  to  compensate  for  this  opening  in  the  shell,  as 
shown  by  the  extensions  on  gaged  lengths  E-63  and  E-64. 

48  Referring  next  to  the  behavior  of  the  shell  at  the  seams, 
Fig.  22  shows  two  groups  of  curves  of  three  lines  each  which  repre- 
sent the  tangential  extensions  on  gaged  lengths  established  on  course 
C  taken  across  the  longitudinal  seam  at  the  middle  and  at  the  edges 
of  the  course. 

49  Curves  C-7  and  C-ll,  representing  the  extension  at  the  edges 
of  the  course  on  the  right  side  of  the  boiler,  coincide  in  places  and 
show  but  slight  divergence  where  they  depart  most  from  the  same  line; 


FIG.  28    MANHOLE  PATCH  AFTER  RUPTURE.    MAXIMUM  PRESSURE  ON  SHELL 

335  LB.  PER  SQ.  IN. 

that  is,  they  indicate  that  uniform  behavior  was  displayed  at  the 
opposite  edges  of  this  course.  Each  deflect  rapidly  under  pressure 
above  150  Ib.  per  sq.  in.,  corresponding  to  a  tensile  stress  of  14,400 
Ib.  per  sq.  in.  on  the  solid  sheet. 

50  At  the  middle  of  the  length  of  the  course,  curve  C-15  showed 
an  increase  in  the  rate  of  extension  at  the  above-mentioned  pressure, 
and  for  each  succeeding  pressure  a  greater  extension  than  that  wit- 
nessed at  the  edges.     Necessarily,  variations  in  the  tangential  exten- 
sions at  different  parts  of  the  length  of  a  seam  would  cause  variations 
in  the  stresses  of  the  solid  metal  of  the  shell  in  those  localities. 

51  In  the  case  of  a  three-course  boiler  with  one  sheet  to  a  course, 
as  found  in  current  construction,  it  would  seem  that  a  double-riveted 


JAMES   E.   HOWARD 


661 


662 


STRAIN  MEASUREMENTS   OF  STEAM   BOILERS 


JAMES  B.   HOWARD 


663 


lap  joint  might  occasion  an  excessive  stress  in  the  solid  sheet  abreast 
the  end  of  the  seam,  under  certain  pressures. 

52  In  the  present  test  the  longitudinal  seams,  being  only  three 
rivet  pitches  apart,  furnish  a  line  from  front  to  rear  of  the  boiler 
across  which  the  extensions  are  greater  than  those  which  are  displayed 
by  the  solid  sheets. 

53  Fig.  23  shows  results  corresponding  to  those  of  Fig.  22  but  per- 
taining to  D,  the  next  course  of  the  boiler.     The  results  are  about 
the  same  on  each,  the  maximum  tangential  extensions  being  dis- 
played at  the  middle  of  the  length  of  the  seams. 

54  Fig.  24  shows  the  extension  of  end  course  A,  across  the  longi- 
tudinal seams  on  either  side  of  the  boiler  and  also  the  extension  of 


FIG.  31  LONGITUDINAL  STRAINS,  ON  TOP  OF  BOILER  IN  VICINITY  OF  DOME 
AND  MANHOLE  PATCHES,  ON  DOME  PATCH,  AND  ACROSS  GIRTH  SEAMS,  AT  90, 
180  AND  270  LB.  PRESSURE 


the  solid  sheet  near  the  girth  rivets  of  the  front  head.  The  diver- 
gent curves  of  this  diagram  indicate  how  differently  in  degree  the  metal 
is  strained  at  the  several  gaged  lengths  of  this  narrow  course.  There 
seems,  however,  no  lack  of  consistency  in  the  behavior  of  the  metal. 
The  strains  were  relatively  such  as  would  be  expected  under  the  con- 
ditions present  in  this  part  of  the  boiler. 

55  The  strains  in  course  E,  at  the  rear  end  of  the  boiler  are  shown 
in  Fig.  25,  where  the  behavior  of  the  shell  was  found  to  be  similar  to 
that  at  the  front  end.  Notwithstanding  the  fact  that  the  results 
appear  consistent  and  the  relations  between  the  different  parts  of 
the  boiler  harmonious,  attention  is  attracted  by  the  variableness  of 
the  strains  as  they  are  found  developed,  according  to  the  position  of 
the  measured  lengths.  The  degree  of  variability  witnessed  in  this 
type  of  boiler,  which  is  certainly  one  of  plain  form,  is  such  as  to  excite 
speculative  interest  in  more  complicated  types. 


664 


STRAIN   MEASUREMENTS   OF   STEAM   BOILERS 


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JAMES   E.   HOWARD 


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STRAIN   MEASUREMENTS   OF   STEAM   BOILERS 


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JAMES  B.  HOWARD 


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STRAIN   MEASUREMENTS   ON   STEAM   BOILERS 


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JAMES   E.   HOWARD 


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STRAIN   MEASUREMENTS   OF   STEAM   BOILERS 


56  The  results  of  the  diagrams,  Figs.  18-27,  refer  to  the  total 
extensions  of  the  gaged  lengths,  that  is,  they  include  the  elastic 
extensions  and  the  permanent  sets  when  sets  have  occurred.  The 
curves  in  Fig.  26  were  plotted  for  the  purpose  of  showing  the  elastic 


FIG.  38  TANGENTIAL  STRESSES,  LB.  PER  SQ.  IN.,  AT  90  LB.  BOILER  PRES- 
SURE. RESULTS  BASED  ON  RESILIENCES.  RIGHT  SIDE  OF  BOILER.  NOR- 
MAL COMPUTED  STRESS,  8640  LB.  PER  SQ.  IN. 


FIG.  39  TANGENTIAL  STRESSES,  LB.  PER  SQ.  IN.,  AT  180  LB.  BOILER  PRES- 
SURE. RESULTS  BASED  ON  RESILIENCES.  RIGHT  SIDE  OF  BOILER.  NORMAL 
COMPUTED  STRESS,  17,280  LB.  PER  SQ.  IN. 

extensions  only,  or  what  is  equivalent  to  the  same,  the  resilience  of 
the  shell  taken  across  the  longitudinal  seam  of  course  D,  right  side. 
The  greater  resilience  of  gaged  length  D-15,  which  was  located  across 
the  longitudinal  seam  at  the  middle  of  its  length,  over  the  amount 
called  for  by  the  modulus  of  elasticity  curve  will  be  noted.  This  might 


JAMES    E.    HOWARD 


671 


be  taken  to  indicate  an  intensity  of  stress  above  the  normal  in  the 
shell  in  that  vicinity,  or  it  may  mean  that  bending  and  shearing 
stresses  at  the  seam  in  addition  to  tensile  stresses  on  the  sheets  modi- 
fied the  results. 


FIG.  40  TANGENTIAL  STRESSES,  LB.  PER  SQ.  IN.  AT  270  LB.  BOILER  PRES- 
SURE. RESULTS  BASED  ON  RESILIENCES.  RIGHT  SIDE  OP  BOILER.  NORMAL 
COMPUTED  STRESS,  25,920  LB.  PER  SQ.  IN.  GAGED  LENGTHS  ON  WHICH  DECIDED 
PERMANENT  SETS  OCCURRED,  INDICATED  BY  A  STAR 


.FiG.  41  TANGENTIAL  STRESSES,  LB.  PER  SQ.  IN.,  AT  90  LB.  BOILER  PRES- 
SURE. RESULTS  BASED  ON  RESILIENCES.  LEFT  SIDE  OF  BOILER.  NORMAL 
COMPUTED  STRESS,  8640  LB.  PER  SQ.  IN. 

57  The  interior  pressure  on  the  boiler  was  increased  from  300  lb., 
the  highest  indicated  on  the  diagrams,  to  335  lb.,  under  which  latter 
pressure  rupture  of  the  manhole  patch  occurred.  Three  of  the  rivets 
were  sheared  by  the  tangential  stress  of  the  shell,  followed,  apparently, 


672 


STRAIN   MEASUREMENTS   OF   STEAM   BOILERS 


by  the  fracture  of  other  rivets  by  tension  on  the  stems,  which  pulled 
off  the  heads  and  finally  tore  the  shell  longitudinally  along  its  upper 
element,  starting  this  fracture  at  a  rivet  hole  of  the  manhole  opening. 
Fig.  28  shows  the  appearance  of  this  fracture. 


FIG.  42  TANGENTIAL  STRESSES,  LB.  PER  SQ.  IN.,  AT  180  LB.  BOILER  PRES- 
SURE. RESULTS  BASED  ON  RESILIENCES.  LEFT  SIDE  OF  BOILER.  NORMAL 
COMPUTED  STRESS,  17,280  LB.  PER  SQ.  IN. 


FIG.  43  TANGENTIAL  STRESSES,  LB.  PER  SQ.  IN.,  AT  270  LB.  BOILER  PRES- 
SURE. RESULTS  BASED  ON  RESILIENCES.  LEFT  SIDE  OF  BOILER.  NORMAL, 
COMPUTED,  STRESS,  25,920  LB.  PER  SQ.  IN.  GAGED  LENGTHS  ON  WHICH  DECIDED 
PERMANENT  SETS  OCCURRED,  INDICATED  BY  A  STAR 


58  The  shell  was  repaired  by  cutting  out  a  portion  of  course  C, 
across  the  top  of  the  boiler  and  putting  in  a  section  the  full  length 
of  the  course  and  about  3  ft.  wide,  measured  on  the  arc.  This  new 


JAMES   B.    HOWARD 


673 


section  was  double-riveted  to  the  shell  at  its  longitudinal  seams.  The 
rivets  were  H  in.  in  diameter  and  had  a  pitch  of  2.87  in.  The  rows 
were  1.53  in.  apart,  with  rivets  staggered,  which,  were,  of  course, 
hand-driven.  The  points  of  the  rivets  were  hammered  down  to 
conical  shape,  low  in  height  and  with  thin  edges.  In  this  re- 
spect they  were  less  substantial  than  the  points  of  the  original 
machine-driven  rivets  of  the  seams. 


<Q 


FIG.  44  TANGENTIAL  STRESSES,  LB.  PER  SQ.  IN'.,  AT  90  LB.  BOILER  PRES- 
SURE. RESULTS  BASED  ON  RESILIENCES.  TOP  OF  BOILER.  NORMAL  COM- 
PUTED STRESS,  8640  LB.  PER  SQ.  IN. 


FIG.  45  TANGENTIAL  STRESSES,  LB.  PER  SQ.  IN.,  AT  180  LB.  BOILER  PRES- 
SURE. RESULTS  BASED  ON  RESILIENCES.  TOP  OF  BOILER.  NORMAL  COM- 
PUTED STRESS,  17,280  LB.  PER  SQ.  IN. 

59  The  hand-driven  rivets  would  not  be  expected  to  hold  the  calk- 
ing as  well  as  the  machine-driven  rivets  by  reason  of  the  difference 
in  their  points,  and  the  test  showed  that  such  weakness  was  the  case. 

60  The  diagram,  Fig.  27,  shows  the  behavior  of  the  seams  of  this 
new  section  of  course  C.    The  flatness  of  the  curves  indicate  how  early 
these  new  seams  began  to  display  rapid  extension,  and  with  so  decided 
a  movement  the  calking  was  soon  disturbed  and  copious  leaks  started. 


674 


STRAIN    MEASUREMENTS    OF   STEAM    BOILERS 


At  the  time  of  presenting  these  notes  no  higher  pressure  has  been 
reached  than  the  rupturing  one  of  335  Ib.  previously  mentioned. 

61  The  strain  measurements  thus  far  described  were  those  which 
were  observed  on  tangential  gaged  lengths.     In  addition  to  this  as 
indicated  in  the  diagrams,  Figs.  15,  16  and  17,  there  were  longitudinal 
gaged  lengths  laid  off  on  the  shell  and  measured. 

62  In  a  plain  cylindrical  shell  the  tangential  extension  of  the  metal 
would  necessarily  be  attended  with  a  definite  amount  of  longitudinal 
contraction,  eliminating  the  effect  of  pressures  on  the  head.    The 
conditions,  however,  which  are  present  in  steam  boiler  construction 
will  generally  prevent  realizing  the  longitudinal  strains  which  would 
be  looked  for  in  a  plain  sheet. 


I, 

M-' 


FIG.  46  TANGENTIAL  STRESSES,  LB.  PER  SQ.  IN.,  AT  270  LB.  BOILER  PRES- 
SURE. RESULTS  BASED  ON  RESILIENCES.  TOP  OF  BOILER.  NORMAL  COM- 
PUTED STRESS,  25,920  LB.  PER  SQ.  IN.  GAGED  LENGTHS  ON  WHICH  DECIDED 
PERMANENT  SETS  OCCURRED,  INDICATED  BY  A  STAR 

63  In  the  present  test  there  were  parts  of  the  boiler  nearly  free 
from  longitudinal  strains,  while  there  were  other  places  in  which  the 
strains  were  reversed,  and  longitudinal  extension  shown  instead  of 
longitudinal  contraction. 

64  In  order  to  determine  whether  the  action  immediately  at  the 
girth  seams  was  represented  by  the  10-in.  gaged  lengths  which  spanned 
them  symmetrically,  other  gaged  lengths  were  established  on  the 
shell,  not  indicated  on  the  diagrams  herewith    presented.     These 
were  in  pairs,  one  being  wholly  on  the  solid  sheet,  the  other  just  step- 
ping on  to  the  adjacent  course.    The  observations  on  these  gaged 
lengths  lead  to  the  same  results,  however,  as  found  on  those  which 
symmetrically  spanned  the  seam. 

65  The  results  of  these  observations  showed  that  along  the  lower 
quarter  of  the  boiler  the  longitudinal  strains   were  contractions; 


JAMES   E.    HOWARD  675 

while  along  the  upper  quarter  they  were  in  part  contractions,  and  in 
part  extensions.  The  strains  observed  at  270  Ib.  pressure  are  entered 
on  two  lightly  printed  photographs,  Figs.  29  and  30.  In  Fig.  29  are 
shown  the  strains  which  were  measured  on  gaged  lengths  1  and  3, 
taken  on  the  solid  sheets  at  the  middle  of  the  lengths  of  the  courses. 
In  Fig.  30  are  shown  the  strains  which  were  measured  on  gaged  lengths 
2  and  4,  taken  across  the  girth  seams.  Minus  signs  before  the  figures 
indicate  contractions  while  plus  signs  indicate  extensions. 

66  It  will  be  observed  that  the  lower  part  of  the  shell  contracted 
longitudinally,  notwithstanding  the  fact  that  the  tubes  were  extended 
by  reason  of  the  exterior  pressures  to  which  they  were  subjected. 


FIG.  47    LAMELLAR  APPEARANCE  OF  METAL,  SHEET  C,  FRACTURED  BY  BEND- 
ING WHILE  AT  A  BLUE  HEAT 


67  This  behavior  calls  for  bending  at  the  flanges  of  the  heads  to 
compensate  for  the  difference  in  direction  of  these  movements.     The 
six  through  braces  would  relieve  the  shell  of  a  portion  of  the  longi- 
tudinal tension  coming  from  the  heads  in  the  upper  half  of  the  boiler. 

68  Longitudinal  gaged  lengths  on  the  upper  part  of  the   shell 
showed  diminished  contractions  over  those  observed  on  the  lower 
portion,  or  displayed  strains  of  extension.    On  the  very  top  of  the 
boiler  the  strains  were  extensions  of  a  pronounced  order. 

69  It  was  found  on  diagonal  gaged  lengths,  laid  off  on  courses 
B  and  D,  upper  quarter  of  the  boiler,  that  greater  extensions  were 
displayed  on  the  converging  diagonals  over  those  of  diverging  direc- 
tions.    The  converging  diagonals,  at  270  Ib.  pressure,  extended  0.0047 
in.  and  0.0042  in.  respectively,  against  0.0036  in.  and  0.0028  in.  dis- 
played on  the  diverging  gaged  lengths. 


676  STRAIN   MEASUREMENTS   OF   STEAM   BOILERS 

70  The  location  of  the  diagonal  gaged  lengths  on  course  D  are 
shown  in  Fig.  14,  similar  lengths  having  been  laid  off  on  course  B. 
These  results  are  entered  in  Fig.  30,  in  addition  to  the  longitudinal 
strains.  The  longitudinal  strains,  all  being  those  of  extension,  observed 
on  the  top  of  the  boiler,  have  been  entered  on  the  diagram,  Fig.  31. 
The  strains  for  each  pressure,  90,  180,  and  270  Ib.  respectively,  are 
given.    The  range  and  variability  of  these  measurements  are  seen 
to  be  very  pronounced. 

71  A  series  of  lightly  printed  photographs,  Figs.  32  to  37  inclusive, 
are  presented,  on  which  are  entered  the  measured  tangential  strains 
observed  at  pressures  of  90,  180  and  270  Ib.  respectively. 

72  The  strains  observed  on  both  the  right  and  the  left  sides  are 
entered,  however,  on  prints  representing  the  right  side  of  the  boiler. 
It  will  be  understood  that  the  longitudinal  seams  of  the  left  side 
were  the  reverse  of  those  on  the  right  side  as  regards  their  respective 
heights.    That  is,  on  the  left  side  the  seams  of  course  B  and  D,  were 
three  rivets  above  instead  of  three  rivets  below  the  others,  as  shown 
in  illustrations  of  the  right  side.    The  tangential  strains  called  for  by 
computation  based  on  a  30,000,000  modulus  of  elasticity  are  stated 
for  each  pressure  in  the  captions  of  the  figures. 

73  The  range  in  measured  strains  above  and  below  the  computed 
amount  will  be  noted  upon  inspection  of  Figs.  32-37.    The  strains  were 
least  in  amount  at  the  heads,  and  generally  greater  rigidity  was  dis- 
played at  the  intermediate  girth  seams  than  in  the  solid  sheets,  under 
the  earlier  pressures.    At  the  middle  of  the  length  of  the  longitudinal 
seams  the  maximum  extensions  were  developed,  witnessed  in  this 
examination  of  the  behavior  of  the  shell. 

74  The  results  thus  far  presented,  with  the  exception  of  those  on 
Fig.  26,  have  included  both  the  elastic  strains  and  the  permanent 
sets  of  the  different  measured  lengths. 

75  The  permanent  sets  have  been  subtracted  from  the  extensions 
and  the  stresses  corresponding  to  these  resiliences  computed,    and 
the  results  entered  on  another  series  of  diagrams,  Figs.  38  to  46 
inclusive.     These  results  show  the  tangential  stresses,  in  pounds  per 
square  inch,  found  in  different  parts  of  the  solid  sheets  of  the  shell 
when  the  boiler  was  subjected  to  pressures  of  90,  180  and  270  Ib., 
respectively. 

76  In  looking  over  those  results  the  usual  influence  of  longitudi- 
nal seams,  such  as  were  used  in  this  boiler,  in  intensifying  the 
tangential  stresses  in  the  adjacent  solid  sheets,  may  be  pointed  out. 
The  excessive  stress  at  the  side  of  the  single-riveted  manhole  patch  is 


JAMES   E.    HOWARD  677 

clearly  shown  in  the  results.  The  high  stresses  at  the  sides  of  the 
safety-valve  nozzle  under  the  maximum  pressure  will  also  be  noted. 

77  While  the  results  are  consistent,  nevertheless  as  an  engineering 
structure  the  distribution  of  stresses  exhibits  a  range  far  beyond  that 
which  is  expected  in  other  classes  of  constructive  work.     The  type 
of  boiler  being  one  of  the  simplest,  the  extension  of  this  method  of 
test  to  other  types  would  seem  desirable.     Such  tests  might  assist 
in  establishing  satisfactory  rules  for  steam  boiler  construction  and 
might  reasonably  be  expected  to  aid  in  the  framing  of  regulations 
governing  allowable  pressures. 

78  Additional  tests  were  carried  out,  in  which  the  effect  of  changes 
in  the  manner  of  supporting  the  boiler  was  inquired  into.     It  was  sup- 
ported on  the  four  end  lugs  in  one  test,  and  again  in  another  test 
most  of  the  weight  was  carried  by  the  middle  lugs.     In  each  case 
there  was  a  modification  in  the  measured  strains,  although  not  in  a 
marked  degree.     At  the  end  of  the  test  the  several  courses  were  seen 
to  have  been  visibly  extended  in  diameter  between  the  girth  seams. 

79  The  chemical  composition  of  the  steel  in  course  C  was  as  fol- 
lows : 

Carbon 0.22 

Manganese 0.43 

Silicon 0.046 

Sulphur 0.028 

Phosphorous 0.043 

It  is  recalled  that  this  particular  brand  of  steel  at  the  time  of  its 
manufacture  was  not  infrequently  found  to  possess  a  decidedly  lam- 
inated structure.  The  laminations  were  not  large,  nor  likely  to  cause 
blisters  in  the  boiler,  but  they  were  in  places  quite  numerous. 

80  The  metal  from  course  C,  the  only  sheet  yet  examined,  was 
found  to  have  a  laminated  structure.     Fig.  47  shows  the  appearance 
of  some  fractured  strips  from  this  course,  which  were  bent  while 
at  a  blue  heat,  in  order  to  develop  the  lamination  of  the  plate  in  a 
pronounced  manner.     The  metal  drifts  well,  a  f  in.  diameter  punched 
hole  having  been  drifted  cold  to  If  in.  diameter  without  rupture. 

81  The  services  of  Mr.  P.  W.  Brunner,  and  J.  W.  Herrity  are 
acknowledged,  whose  skill  as  manipulators  is  shown  by  the  internal 
evidence  of  reliability  which  these  measurements,  taken  by  them, 
furnish. 


DISCUSSION 

FRANCIS  B.  ALLEN.  The  paper  contains  some  very  interesting 
data  which  are  more  complete  than  any  we  have  ever  had  so  far  as  I 
know,  in  tests  of  boilers  of  this  description.  In  my  own  experience, 
it  is  a  very  difficult  problem  to  convince  a  manufacturer  when  a 
battery  of  boilers  has  given  good  service  and,  superficially  at  least, 
is  without  patches  or  other  evidence  or  deterioration,  that  it  is 
necessary  to  reduce  pressure  in  order  to  maintain  so  far  as  possible 
the  full  factor  of  safety.  I  have  in  mind  a  set  of  boilers  which  was 
in  operation  for  27  years,  in  which  the  original  pressure  allowed  was 
85  Ib.  By  successive  cuts  as  the  boilers  increased  in  age,  this  pres- 
sure was  reduced  to  60  Ib.  and  upon  inspection  a  recommendation  was 
made  that  the  pressure  be  reduced  to  50  Ib.,  or  preferably  that  newer 
and  stronger  boilers  be  submitted.  This  meant  an  expense  of  thou- 
sands of  dollars  and  the  manufacturers  naturally  wished  to  use  the 
boilers  a  little  longer  and  so  make  a  greater  return  upon  the  invest- 
ment. 

In  the  belief,  however,  that  it  would  not  be  advantageous  to  take 
the  risk  involved,  they  were  taken  out;  and  the  test  which  the  paper 
describes  established  the  fact  that  while  there  was  an  ample  factor 
of  safety  according  to  the  requirements  of  law  and  custom,  the  recom- 
mendation to  remove  the  boilers  was  fully  justified  because  they  had 
approached  the  danger  line  as  closely  as  should  be  allowed.  The  fact 
that  these  boilers  described  in  the  paper  were  exceptionally  good 
and  had  been  carried  by  one  organization  and  insured  by  another  from 
the  time  they  were  put  into  commission  until  they  were  taken  out, 
makes  the  record  and  data  unusually  valuable. 

THE  AUTHOR.  The  two  boilers  under  consideration  present  fea- 
tures of  interest  because  of  the  long  term  of  their  service  and  their 
excellent  condition  when  the  tests  were  made.  Originally,  these 
boilers  were  run  under  90  Ib.  steam  pressure  which  was  eventually 
reduced  to  60  Ib.,  the  pressure  carried  at  the  time  they  were  taken  out 
of  service. 

678 


CLOSURE  679 

An  inspection  of  the  interior  of  the  first  boiler  showed  little  or  no 
scale  on  the  sheets,  excepting  a  limited  amount  of  loose  material  on 
the  bottom  of  the  boiler.  The  upper  row  and  side  vertical  rows  of  the 
tubes  were  free  from  deposit,  while  the  interior  ones  had  a  deposit 
on  the  rear  quarter  or  half  and  at  their  immediate  front  ends.  The 
tubes,  however,  were  free  from  pitting  and  general  corrosion. 

The  condition  of  the  boilers  was  such  that  the  results  of  the  strain 
measurements  may  be  taken  as  representative  of  the  behavior  of 
boilers  of  their  type  in  respect  to  the  distribution  of  stresses  in  different 
parts  of  the  shell  when  under  pressure. 

In  the  test  of  the  first  boiler,  such  copious  leakage  at  the  single 
riveted  longitudinal  seam  of  the  dome  occurred  at  266  Ib.  pressure 
that  its  removal  was  necessitated.  At  that  time,  the  metal  at  the 
base  of  the  dome  was  overstrained  and  lines  of  scale  were  detached, 
showing  that  the  elastic  limit  of  the  metal  had  been  passed.  The 
manhole  frame  was  the  next  to  yield,  fracturing  at  270  Ib.  pressure. 
Several  of  the  stays  at  the  front  head  at  295  Ib.  pressure  ruptured. 
The  test  was  then  discontinued  and  the  boiler  dismantled.  The  metal 
from  the  shell  and  some  of  the  tubes  was  reserved  for  subsequent 
examination  and  test. 

Prior  to  testing  the  second  boiler  it  was  divested  of  its  dome  and 
manhole  frame  and  the  heads  were  strengthened  by  means  of  six 
through-braces.  With  this  boiler  a  rupturing  pressure  was  reached 
at  335  Ib.,  the  rupture  occurring  at  the  single-riveted  patch  covering 
the  manhole  opening.  A  section  of  this  course  was  cut  out  and  the 
shell  repaired  with  a  new  piece  of  plate,  which  was  double-riveted. 
Hand-holes  necessary  for  riveting  were  made  in  the  new  plate.  No 
higher  pressure  has  yet  been  reached  than  the  earlier  one  of  335  Ib., 
leakage  overcoming  the  pumps  and  taking  place  at  the  longitudinal 
seams  and  particularly  at  the  new  hand-riveted  seams.1 

Concerning  the  distribution  of  the  stresses  in  the  shell,  at  few  of 
the  measured  lengths  was  the  tangential  extension  of  the  shell  found 
to  correspond  closely  to  the  computed  extension,  although  there  were 
places  where  there  was  full  agreement.  Generally,  the  tangential 
extensions  in  the  vicinity  of  the  girth  seams  were  less  than  the  com- 
puted values.  Naturally  the  edges  of  the  end  courses  over  the  heads 
displayed  only  a  limited  amount  of  extension. 

Across  the  longitudinal  seams,  taken  at  the  middle  of  the  lengths  of 

JA  pressure  of  370  Ib.  has  since  been  reached.  The  sheets  show  further 
deformation  but  have  not  yet  ruptured. 


680  STRAIN  MEASUREMENTS  OF  STEAM  BOILERS 

the  several  courses,  the  extensions  were  greater  than  called  for  by 
computation  for  the  solid  sheets.  This  increased  yielding  at  the  lon- 
gitudinal seams  became  more  pronounced  as  higher  pressures  were 
successively  applied,  the  extensions  in  the  vicinity  of  the  girth  seams, 
however,  remaining  less  than  the  normal  amount. 

A  place  characterized  by  unusual  rigidity  was  found  on  the  top  of 
the  boiler  in  the  immediate  vicinity  of  the  double-riveted  manhole 
patch  and  the  girth  seam,  while  in  the  next  course  at  the  side  of  the 
manhole  patch  unusual  extension  was  displayed. 

The  relative  rate  of  extension  observed  under  early  pressures  was 
maintained  without  material  change  under  the  subsequent  higher 
pressures. 

The  longitudinal  strains  were  found  to  be  contractions  on  the 
lower  part  of  the  shell,  in  part  contractions  and  in  part  extensions  on 
the  upper  part  of  the  shell,  while  on  the  top  of  the  boiler  they  were  all 
strains  of  extension. 

The  method  of  measured  strains  illustrated  in  these  results  is  a 
convenient  one  for  extending  the  scope  of  research  work  beyond  the 
usual  limits  of  laboratory  tests  as  conducted  in  testing  machines. 
Knowledge  pertaining  to  the  distribution  of  stresses,  important  in 
structures  of  all  kinds,  may  be  ascertained  in  this  manner.  The  con- 
structive merits  of  different  types  of  boilers  admit  of  being  ascertained 
by  the  method  of  measured  strains. 

It  would  seem  feasible,  judging  from  the  indications  of  the  present 
tests,  to  determine  the  merits  of  different  types  by  means  of  observa- 
tions confined  within  the  limits  of  the  usual  hydrostatic  test  pressures, 
as  applied  to  new  boilers.  That  is,  an  adequate  opportunity  is  pre- 
sented in  the  hydrostatic  test  to  acquire  this  information  and  in  no 
wise  impair  the  strength  of  the  shell  or  other  parts  by  reason  of  having 
made  such  strain  measurements. 

The  obvious  value  of  such  information  will  not  require  further  men- 
tion. It  is  believed  that  herein  is  presented  a  method  of  test  which 
will  lend  material  aid  in  furnishing  a  rational  basis  on  which  to  estab- 
lish rules  regarding  allowable  steam  pressures. 

With  the  present  knowledge  available  on  the  effects  of  repeated 
stresses  in  destroying  the  integrity  of  structures,  it  is  apparent  that 
information  pertaining  to  the  behavior  of  structures  under  work- 
ing loads  is  desirable.  Most  failures  emphasize  the  need  of  more 
complete  data  on  working  conditions  rather  than  any  deficiency  of 
knowledge  on  the  ultimate  strength  of  the  component  parts  taken 
individually. 


SYMPOSIUM  ON  STEEL  PASSENGER 
CAR  DESIGN 

No.  1388  a 

INTRODUCTION 

BY  H.  H.  VAUGHAN,  MONTREAL,  CANADA 
Member  of  the  Society 

The  advent  of  the  steel  passenger  car  has  brought  with  it  many 
new  problems  and  an  opportunity  for  more  diverse  opinions  than  any 
other  change  that  has  taken  place  in  car  equipment.  The  construction 
of  the  wooden  passenger  car  developed  along  fairly  uniform  lines. 
The  varieties  of  framing  were  few  and  the  differences  unimportant, 
while  the  introduction  of  steel  platforms,  wide  and  narrow  vestibules, 
reinforced  end  and  sill  construction  and  similar  improvements  oc- 
curred gradually,  and  with  practically  similar  designs  on  all  railroads. 
The  change  from  wood  to  steel  in  freight  car  construction  resulted  in 
the  abandonment  of  designs  that  had  almost  become  standardized  and 
the  introduction  of  many  new  types,  but  in  this  case  the  principal 
problem,  other  than  that  of  obtaining  satisfactory  designs,  has  been 
the  extent  to  which  it  was  advisable  to  use  composite  or  all-steel 
construction. 

2  In  the  case  of  the  passenger  car,  the  types  to  be  employed  will 
probably  not  be  changed  by  the  substitution  of  steel  for  wood.  The 
increase  in  capacity  that  has  taken  place  in  freight  equipment  cannot 
be  duplicated  in  passenger  cars,  and  there  appears  to  be  no  tendency 
at  present  toward  any  increase  in  length  or  carrying  capacity.  The 
questions  that  now  confront  us  relate  rather  to  the  design  and  con- 
struction of  cars  of  the  present  type  and  of  the  materials  that  may  be 
advantageously  employed  in  place  of  the  wood  which  has  been  used 
for  so  long.  They  are  complicated  by  the  necessity  of  providing 
for  greater  safety  for  the  passengers  than  was  secured  in  the  wooden 
car,  with  an  equal  degree  of  comfort  and  the  difficulty  of  anticipating 
the  behavior  of  this  new  equipment  in  the  case  of  accident.  Certain 
difficulties  such  as  the  best  systems  for  heating,  lighting  and  ventila- 

Presented  at  the  New  York  Meeting,  April  1913,  of  THE  AMERICAN  SO- 
CIETY OF  MECHANICAL  ENGINEERS. 

17 


18  INTRODUCTION 

tion,  are  common  to  both  steel  and  wood  construction,  and  improve- 
ments in  these  matters  pertain  to  general  progress  rather  than  the  use 
of  steel  construction.  The  following  list,  while  probably  incomplete, 
outlines  in  a  brief  way  the  important  variations  that  must  be  consid- 
ered in  deciding  on  the  preferable  construction  of  steel  passenger 
equipment : 

Framing    Steel  underf rame 

AH-stee,   fnune 

Outside  finish Plated 

Sheathed 
Eoof    construction Clear  story 

Circular 
Inside  finish Steel 

Wood 

End    construction Design  and  strength 

Floor   Design  and  material 

Insulation Material 

No  doubt  questions  of  equal  importance  have  been  omitted,  and  in 
many  cases  those  mentioned  require  careful  consideration  with  regard 
to  degree,  as  for  instance,  the  strength  of  the  framing  or  the  thickness 
of  the  insulation.  The  list  illustrates,  however,  the  diversity  of 
possible  solutions  of  the  preferable  steel  passenger  car,  and  the  follow- 
ing personal  opinions  are  presented  for  the  purpose  of  opening  the 
discussion : 

3  The  steel  underframe  does  not  appear  to  be  a  satisfactory 
or   permanent   development.      There   is   but   little   saving   either   in 
weight  or  cost  over  the  all-steel  construction,  and  it  is  difficult  to  see 
how  the  same  strength  in  case  of  accident  can  be  obtained.    Experience 
will  show  whether  the  wood  superstructure  can  be  secured  in  such  a 
way  as  to  prevent  working  as  the  car  gets  old,  but  as  it  cannot  be 
arranged   to   carry   any   weight   this   appears   questionable.      It   can 
hardly  be  regarded  except  as  an  intermediate  step  between  all-wood 
and  all-steel  construction. 

4  In  all-steel  •  construction  the  side-girder  car  presents  advan- 
tages, but  as  in  freight  construction,  both  types  will  probably  persist. 
The  side-girder  construction   obtains  greater   strength   on   the   side 
framing  without  superfluous  weight,  and  it  is  possible  that  greater 
framing  strength  may  prove  necessary.     With  equal  strength  of  side 
framing  the  side-girder  car  may  be  made  lighter  than  the  center-girder 
type,  and  the  weight  of  steel  passenger  cars  is  one  of  the  most  serious 
problems  to  be  faced  by  any  railroad  not  having  a  level  line.    Ameri- 


H.  H.  VAUGHAN  19 

can  passenger  equipment  was  already  excessively  heavy  per  passenger 
carried  with  wood  construction,  and  the  use  of  steel  has  increased 
this  weight  from  10  per  cent  to  20  per  cent,  which  is  a  most  serious 
matter.  Apparently  side-girder  cars  as  so  far  constructed  have  a 
decided  advantage  over  the  center-girder  type  in  their  light  weight  and 
greater  strength  in  case  of  accident  tending  to  crush  in  the  side  of  the 
car.  This  will  probably  lead  to  the  use  of  this  type  on  roads  on  which 
weight  is  of  importance. 

5  In  spite  of  the  many  advantages  of  the  sheathed  car  in  case 
of  construction  and  maintenance,  it  appears  that  the  cost  and  weight 
of  the  additional  metal  will  prevent  its  extensive  use.    This  question 
is  chiefly  one  of  appearance  and  convenience,  and  is  of  minor  im- 
portance. 

6  The  circular  roof  has  been  extensively  introduced  on   steel 
passenger  cars  on  account  of  its  lightness  and  simplicity  of  con- 
struction.    It  has  the  objection  that  deck  sash  ventilation  cannot  be 
employed.     The  Pullman  Company  while  using  the  clear-story  roof 
have,  however,  discontinued  the  use  of  deck  sash  ventilation,  so  that 
evidently  in  their  opinion  this  objection  is  not  important.     The  deck 
sash  is,  however,  of  value  in  a  standing  car,  and  when  properly  screened 
is  certainly  advisable  in  hot  weather,  especially  when  the  road  is 
dusty.      The   Canadian   Pacific   Railway  have   compromised  on  this 
question  and  are  using  a  roof  of  approximately  circular  form  with 
deck   sash.      The   strength   and   simplicity   of   the   circular   roof   is 
retained  with  the  ventilating  qualities  of  the  clear  story  type. 

7  The  preferable  material  for  inside  finish  is  a  matter  for  future 
decision.    With  the  ample  protection  afforded  by  a  steel  car  against 
accident,  there  does  not  appear  to  be  any  objection  to  wood  inside 
finish  on  the  ground  of  safety.    It  is  more  ornamental  than  steel  and 
a  better  insulator.    Probably  on  no  question  in  passenger  car  design  is 
opinion  so  divided  amongst  both  railroad  and  car  builders.     There  is 
today  very  little  difference  in  cost,  and  it  certainly  appears  probable 
that  in  the  future  the  tendency  will  be  to  adopt  steel  interior  finish  if 
not  entirely,  at  any  rate  to  a  great  extent. 

8  The    construction    of    the    ends    of    the    cars    has    received 
considerable  attention,   and  the  strength  now  usually  employed  is 
enormously  greater  than  anything  attempted  in  wood  construction. 
Several  excellent  designs  have  been  devised,  which  will  probably  be 
referred  to  in  another  paper. 

9  The  floor  construction  in  steel  cars  is  entirely  different  from 
that  in  wooden  cars,  and  is  usually  of  metal  covered  with  a  flexible 


20  INTRODUCTION 

cement.  In  constructing  a  sample  car  for  the  Canadian  Pacific 
Railway  the  writer  used  in  addition  an  underfloor  covered  with  insu- 
lating material,  and  covered  the  cement  with  y2  in.  of  cork.  This  car 
was  also  exceptionally  well  insulated  at  the  sides,  2  in.  of  cork  being 
used  next  the  outside  plating.  Tests  during  the  past  winter  have 
shown  that  this  car  is  actually  warmer  than  the  ordinary  wooden  car, 
the  same  amount  of  heating  surface  being  used  in  both  types.  The 
floor  was  tested  by  taking  the  temperature  of  water  standing  in  cans 
on  the  floor,  there  being  no  practical  difference  between  the  results 
in  the  wood  and  steel  cars.  The  question  of  insulation  is  an  important 
one,  both  in  hot  and  cold  weather,  and  while  other  insulation  might 
no  doubt  be  equally  effective,  it  is  interesting  to  be  able  to  advise 
that  with  proper  insulation  there  is  no  question  of  the  steel  car  being 
satisfactory. 


No.  1388  & 

PROBLEMS  OF  STEEL  PASSENGER  CAR 

DESIGN 

BY  W.  F.  KIESEL,  JR.,  ALTOONA,  PA. 
Member  of  the  Society 

Whenever  it  becomes  necessary  to  adopt  a  policy  representing  a 
complete  departure  from  existing  policies  involving  a  new  theoretical 
structure  from  foundation  up,  many  problems,  some  entirely  new, 
have  to  be  solved.  The  increasing  cost  of  lumber,  the  desire  for 
longer  and  stronger  cars,  and  other  considerations  indicated  the 
desirability  of  making  a  determined  effort  to  develop  a  satisfactory 
steel  passenger  car.  The  object  of  this  paper  is  to  review  a  few  of  the 
problems  encountered,  beginning  with : 

2  First:    Can  we  afford  it,  and  what  will  it  cost,  compared  with 
wooden  cars  ?    Tentative  designs  were  prepared  and  carefully  analyzed 
by  a  committee  of  representatives  of  carbuilders  and  railroads.     The 
summary  of  their  report  was  that  at  first  steel  passenger  cars  would 
cost  approximately  20  per  cent  more  per  passenger  than  wooden  cars 
of  the  best  existing  types,  but  that  the  steel  cars  would  probably  cost 
much  less  to  maintain.     They  also  reported  that  on  account  of  the 
increasing  cost  of  good  lumber,  and  the  probable  decreasing  cost  of 
manufacturing  steel  cars,  not  many  years  would  elapse  before  the  cost 
of  steel  cars  would  be  no  more  than,  if  as  much  as,  wooden  cars.    Those 
who  have  been  in  close  touch  with  the  development  of  the  steel-car 
industry  know  that  at  the  present  time  steel  cars  cost  no  more  than 
equivalent  wood  cars. 

3  Second:   Shall  the  cars  be  all  steel,  or  steel  frame  with  wood 
lining?    Differences  of  opinion  still  exist  on  this  point.     Both  types 
of  car  have  been  built,  and  each  has  strong  advocates. 

4  In  the  all-steel  car  the  steel  lining  can  be  securely  riveted  to 
tlie  framing  and  adds  somewhat  to  the  strength  of  the  complete  struc- 
ture, but  as  steel  is  a  good  conductor  it  carries  away  the  heat  of  a 
body  coming  in  contact  with  it,  and,  therefore,  will  always  feel  cold, 
even  when  the  temperature  in  the  car  is  sufficiently  high.     Satisfac- 
tory results  have  been  realized  from  the  use  of  a  double  steel  lining 

Presented  at  the  New  York  Meeting,  April  1913,  of  THE  AMERICAN  SO- 
CIETY OF  MECHANICAL  ENGINEERS. 

21 


22  PROBLEMS  OF  STEEL  PASSENGER  CAR  DESIGN 

between  seats,  forming  a  hot-air  duct,  extending  from  the  heater  pipes 
to  the  window  sill,  with  outlet  through  small  holes  in  the  lining  proper, 
located  immediately  below  the  window  sill  in  the  lining  proper. 

5  Wood   lining   requires   considerable   wood   furring,   and   adds 
weight  to  the  car  without  adding  to  the  strength.    As  the  steel  frame 
of  a  long  passenger  car  may  vary  as  much  as  %  in-  between  extremes 
of  temperature,  it  is  necessary  to  make  allowance  in  the  construction 
of  the  wood  lining  for  this  variation  in  length.    As  a  car  with  metal 
lining  riveted  to  the  framing  has  the  advantage  in  strength,  weight, 
and  cost,  it  will  gain  in  favor;  in  fact,  it  would  be  at  present  uni- 
versally preferred  if  all  railroad  shops  had  practical  experience  with 
steel  lining,   and  the  necessary  proficiency  and  machinery  for  its 
manufacture. 

6  Third:    Insulation.    Three  general  principles  have  been  used 
for  car  insulation:      (a)    Wood  lining;    (b)    by  placing  insulating 
material  on  the  outside  of  steel  lining;   (c)   by  placing  insulating 
material  on  the  outside  of  the  steel  lining,  and  on  the  inside  of  the 
steel  sheathing. 

7  Experiments  have  been  made  also  with  other  methods,  such 
as  completely  filling  the  space  between  sheathing  and  lining  with 
block  magnesia  and  magnesia  cement.     The  problem  that  presents 
itself  is:    Given  a  car  body  with  a  comparatively  smooth  exterior 
surface  protected  by  several  coats  of  paint,  double  walls,  painted  on 
both  sides — if  of  steel,  isolated  air  spaces,  rather  large  in  volume, 
between  the  walls,  an  inside  cubic  volume  in  which  the  air  must  be 
continually  renewed,  and  a  window  surface  of  about  one-third  of  the 
area  of  the  side  walls.    When  single  windows  are  used  the  air  close  to 
the  windows  is  cold  in  winter,  and  warm  in  summer.    Double  windows 
improve  the  situation  materially. 

8  Experiments   made   to   determine   the   difference   between   a 
wooden  and  a  steel  coach,  with  doors  and  windows  closed,  standing 
on  a  siding  exposed  to  the  sun  in  hot,  summer  weather,  showed  a 
difference  of  one  to  two  degrees  in  favor  of  the  wooden  coach.     One 
day's  readings  showed  an  average  of  one  degree  difference  in  tempera- 
ture in  favor  of  the  steel  coach,  which  had  insulation  only  on  the 
outside  of  the  lining.    The  results  of  several  years'  experience  indicate 
that  the  lining  must  be  insulated  throughout,  and,  if  the  spaces  be- 
tween lining  and  sheathing  are  properly  isolated,  little  is  gained  by 
insulating  the  sheathing,  and  more  will  be  gained  by  the  use  of 
double  windows.      Furthermore,   the   heat  lost   in   cold  weather  by 
conduction  through  and  radiation  from  the  walls,  in  cars  with  insula- 


W.  F.  KIESEL,  JR.  23 

tion  on  the  lining  alone,  is  negligible  when  compared  with  the  heat 
carried  off  by  adequate  ventilation. 

9  Fourth:    Protection  and  safety  of  passengers.     This  problem 
involves  providing  adequate  strength  for  carrying  the  load,  also  to 
prevent  collapse  or  crushing  in  wrecks,  and  efficient  brakes. 

10  The  laws  governing  load-carrying  strength  are  well  known, 
but  this  cannot  be  said  of  the  laws  governing  wrecks'.     Each  wreck 
forms  a  separate  study,  and  we  seldom  find  two  that  can  be  placed  in 
the   same   class.     The   study   of   wrecks,   which,    unfortunately,    do 
occur,  shows  that  the  car  underframe  must  be  reasonably  strong  to 
resist  end  strains,  that  the  ends  of  the  superstructure  must  be  rein- 
forced with  strong  vertical  members,   and  that  the  car  must  not 
collapse  when  rolled  down  an  embankment.    The  gradual  elimination 
of  crossings  at  grade  has  materially  decreased  the  danger  of  strains 
directed  against  the  sides  of  the  car. 

11  Early  experience  with  steel  freight  cars  showed  clearly  that 
the  men  handling  cars  in  yards  believed  that  all  cars  built  of  steel 
could  withstand  much  rougher  handling  than  wooden  cars.    Although 
the  resultant  damage  to  both  kinds  of  freight  cars  had  its  disadvan- 
tages, it  developed  a  better  knowledge  of  the  relative  value  of  steel 
and  wood  in  car  construction,  led  the  designer  to  abandon  the  basis 
of  ultimate  strength  of  the  material,  and  to  substitute  the  basis  of 
elastic  limit,  and  finally  to  select  a  ratio  of  4  to  1  as  the  relation  of 
the  elastic  limit  of  steel  as  used  in  cars  to  that  of  good  timber. 

12  That  not  all  designers  of  steel  passenger  cars  had  the  advan- 
tage of  this  knowledge,  or  profited  by  this  experience,  is  evidenced 
by  some  of  the  car  designs  which  have  been  illustrated  in  the  technical 
papers  in  the  past  years  and  which  proved  fundamentally  defective. 

13  Selecting  from  the  last  generation  of  wooden  cars  one  used 
in  heavy  trunk  line  service,  with  four  5-in.  by  9-in.  wooden  sills 
bunched  together  near  the  center,  and  so  located  as  to  be  nearly 
uniformly  affected  by  the  end  strains,  steel  platforms  with  draft  gear 
securely  attached,  and  the  remainder  of  the  car  to  correspond,  the 
analysis  of  its  end-shock  resisting  capacity  leads  to  the  consideration 
of  the  elasticity  of  the  material,  the  transverse  bracing  preventing 
buckling,  the  concentration  of  strength  near  the  longitudinal  center 
line  of  car,  and  the  reinforcement  at  the  platforms. 

14  The  wooden  car,  therefore,  meets  many  of  the  requirements 
enumerated  before.    A  corresponding  steel  car  should  have  a  center  sill 
area  of  45  sq.  in.  braced  against  buckling,  a  strong  and  efficient  draft 
gear  as  a  substitute  for  the  elasticity  of  the  wood,  and  a  ratio  of  0.04 


24  PROBLEMS  OF  STEEL  PASSENGER  CAR  DESIGN 

for  stress  to  end  force,  the  calculations  to  include  consideration  of 
lever  arm  of  force  below  neutral  axis  of  the  center  sills.  For  lighter 
service  a  steel  car  with  center  sill  area  of  32  sq.  in.  and  a  ratio  of  0.0>5 
for  stress  to  end  force  may  be  considered  as  a  substitute  for  a  wooden 
car  with  four  4-in.  by  8-in.  sills  bunched  near  the  center  of  the  car. 
The  use  of  steel  permits  a  distribution  of  material  to  better  advantage 
than  is  possible  with  wood.  The  box  girder  center  construction  is 
continually  gaining  in  popularity,  the  strong  vertical  members  at  car 
ends,  to  prevent  one  car  overriding  and  penetrating  the  superstruc- 
ture of  another  car,  are  now  considered  a  necessity,  and  a  super- 
structure, including  roof  sufficiently  strong  to  bear  the  car  when 
turned  upside  down  without  collapsing,  is  very  desirable. 

15  To  avoid  making  this  paper  too  long  other  interesting  prob- 
lems will  be  omitted,  but  the  truck  problem  deserves  brief  consideration. 
There  are  four-wheel  and  six-wheel  trucks.    They  have  414-in.  by  8-in., 
5-in.  by  9-in.,  5y2-m.  by  9-in.  and  S^-in.  by  10-in.  journals. 

16  The  impression  that  cars  with  six- wheel  trucks  necessarily 
have  better  riding  qualities  than  those  with  four-wheel  trucks  has, 
proved  to  be  incorrect.     The  substitution  of  four-wheel  trucks  for 
six-wheel  trucks  saves  about  18,000  Ib.  per  car.     Increased  journal 
bearing  surface  obtained  by  an  increase  of  diameter  of  journal  only 
is  of  little  or  no  benefit  in  preventing  hot  boxes,  because  the  periphery 
velocity  increases  in  the  ratio  of  the  ,  diameters.     The  weight  per 
journal  should  not  exceed  1500  Ib.  per  in.  length.    A  long  spring  base, 
low-lying  center  plate,  and  anchoring  the  dead  levers  to  the  car  body 
instead  of  to  the  truck  frame  promote  smooth  action  and  easy  riding 
at  all  times!     The  equalizing  springs  should,   therefore,   be  placed 
as  near  to  the  journal  boxes  as  possible,  or  directly  over  the  boxes, 
and  the  bolster  springs  should  be  on  or  near  the  center  line  of  truck 
sides.    If  the  dead  levers  of  the  truck  brake  are  anchored  to  the  car 
body,  the  truck  frames  have  no  tendency  to  tip  up  when  the  brakes 
are  applied,  and  the  jarring  effect  is  entirely  eliminated.     A  special 
axle  with  5y2-in.  by  11-in.  journal  for  passenger  cars  would  be  of 
material  benefit,   would   permit   using   four-wheel   trucks   under   all 
coaches  and  60-ft.  baggage  cars,  and  longer  cars  with  six-wheel  trucks 
would  have  sufficient  margin  for  the  excessive  loads  sometimes  en- 
countered and  the  danger  of  hot  boxes  would  be  avoided. 


JSTo.  1388  c 

UNDERFRAMES  FOR  STEEL  PASSENGER 

CARS 

BY  JOHN  McE.  AMES,  NEW  YORK 
Member   of   the   Society 

This  paper  will  be  confined  to  underframes  of  steel  passenger  cars 
for  through  service,  or  those  at  least  70  ft.  long,  and  will  not  attempt 
to  discuss  those  of  suburban  or  individual  service,  whose  underframes 
are  not  subjected  to  the  same  severe  service  strains.  - 

2  The  underframe  is  called  upon  to  perform  several  functions. 
Not  only  must  it  sustain  the  weight  of  the  superstructure  and  load, 
but  withstand  impact,  oscillation  and  pulling  strains  without  distor- 
tion.    Were  it  not  for  these  conditions  the  underframe  might  be 
considered  as  a  bridge  resting  upon  the  center  plates  and  side  bearings 
as  piers.    Were  we  to  design  to  meet  only  the  carrying  requirements 
the  problem  would  not  be  difficult,  but  the  design  must  also  be  com- 
mercial, not  over  heavy  and  in  addition  sufficiently  strong  to  resist 
impact;  commercial  in  that  plates  and  shapes  employed  are  such  as 
may  readily  be  secured  from  the  steel  mills,  and  not  so  heavy  as  to 
bring  undue  work  upon  either  the  hauling  locomotive,  rails,  frogs, 
bridges,  etc. 

3  The  natural  division  of  such  designs  is: 

a  Underframes  designed  to  carry  equally  on  all  sills 
b  Underframes  designed  to  carry  on  center  sills  only 
c  Underframes  designed  to  carry  on  sides  only 
c  Underframes  designed  to  carry  on  sides  and  center  sills 

4  Each  of  these  types  has  its  partisans  and  each  type  is  in 
successful  operation  today.     The  first  is  the  type  used  abroad  almost 
universally  and  at  home  for  repairs  under  wooden  cars,  the  bodies  of 
which  are  too  good  to  destroy  but  need  better  underframing.     With 
most  of  the  foreign  cars  the  body  rests  upon  and  is  bolted  to  the 
underframe  from  which  it  may  readily  be  removed.     The  buffing  and 
draft  conditions  differ  from  ours  in  that  the  buff  is  taken  through 


Presented  at  the  New  York  Meeting,  April  1913,  of  THE  AMERICAN  SO- 
CIETY OF  MECHANICAL  ENGINEERS. 

25 


26 


UNDERFRAMES  FOR  STEEL  PASSENGER  CARS 


the  side  sills  by  the  use  of  separate  side  buffers,  and  the  draft  through 
the  center  sills  thus  permitting  a  distribution  of  metal  in  each  sill 
member  that  may  produce  uniform  stress. 

5  An  example  of  the  first  type  designed  for  a  wooden  super- 
structure, consists  of  four  deep  sills  of  what  is  known  as  the  "fish- 
belly"  type  (Fig.  1).  These  center  sills  are  composed  of  5/16-in. 
plates,  30  in.  deep  at  the  center  with  3  in.  by  3  in.  by  %  in.  angles 
riveted  along  the  top  and  bottom  edges ;  the  plates  reduced  to  a  depth 


Section  at  Draft  Si  1 1 

FIG.  1     TYPE  a:  WEIGHT  OP  CAR  CARRIED  EQUALLY  ON  CENTER  AND  SIDE  SILLS 

of  1>2%  in.  over  the  bolster.  The  center  sills  have  a  square  inch 
section  of  37  at  the  center,  just  as  the  side  sills,  and  26  at  the  draw 
gear.  One  disadvantage  in  these  long  plate  sills  is  that  when  punching 
the  line  of  holes  along  the  edges  the  plate  becomes  distorted  and 
wavy.  It  is  then  difficult  to  rivet  the  angles  in  place  and  obtain  their 
full  value.  Again,  in  case  of  accident  and  the  dropping  of  the  under- 
frame  upon  the  roadway,  the  bottom  angles  are  bent  or  broken,  making 
a  difficult  repair  operation. 

6  In  general  the  deep  side  sill  has  been  discarded  because  of  the 
difficulty  of  inspection  beneath  the  car.  The  deep  center  sill  is  much 
in  vogue  at  present  because  it  looks  strong,  but  on  a  car  with  deep 
center  sills  inspection  must  be  made  of  the  parts  attached  to  the 
underframe  from  one  side  of  the  car  at  a  time,  and  the  introduction 
of  axle  light  equipment  becomes  difficult  on  account  of  the  interference 
with  the  deep  sills.  Again,  to  sustain  its  own  weight  without  deflec- 
tion on  a  60  ft.  span,  too  much  weight  of  metal  is  required  to  make 
such  a  sill  economical. 


JOHN  MC  E.  AMES 


27 


7  Of  the  second  type,  that  is,  with  the  whole  weight  to  be  carried 
on  the  center  sills,  a  common  form  (Fig.  2)  has  center  sills  of  two 
special  18-in.  channels  with  %-in.  cover  plates  top  and  bottom,  all 
sections  extending  full  length  of  the  car  in  one  piece.  The  box  girder 
so  formed  has  a  square  inch  section  of  50,  and  the  superstructure  load 
is  transferred  to  these  sills  by  means  of  four  cross  bearers,  two  of 
which  take  the  place  of  the  body  end  sills  in  other  design.  There  are 
no  side  sills  as  such,  the  angles  here  shown  simply  forming  the  attach- 
ment for  the  superstructure.  The  parts  are  usually  assembled  with 
the  bottom  of  the  sills  upward  and  allowed  to  deflect.  The  girder  is 
then  reversed  and  the  camber  straightens  out  by  the  weight  of  the 


KP—/7  _^ 

"     *Jr.  u    ~ 


FIG.  2     TYPE  5:  WHOLE  WEIGHT  CARRIED  ON  CENTER  SILLS 


metal.  The  sills  are  the  same  depth  and  section  throughout  their 
entire  length  and  with  this  construction  a  truck  of  special  design  must 
be  used,  the  center  plate  of  which  must  be  nearer  the  rail  than  usual. 
The  weight  of  the  body  rests  upon  the  side  bearings  as  well  as  the 
center  plate.  About  20  sq.  in.  of  metal  in  the  sides  is  available  to 
help  sustain  the  load.  The  service  given  by  this  underframe  has  been 
excellent. 

8  The  third  type,  with  all  the  weight  carried  by  the  car  sides 
has  the  center  sills  used  only  for  buffing  and  pulling.  An  example 
shown  in  Fig.  3  has  two  I-beams  running  full  length  of  the  car  in  one 
piece,  with  a  square  inch  sectional  area  of  23.  They  are  held  up  by 
the  three  cross  bearers  which  pass  under  and  are  attached  to  them. 
There  are  no  side  sills,  the  carrying  members  being  the  sides  of  the 
car.  These  members  are  composed  of  %-in.  plates,  about  36  in.  deep, 


28  UNDERFRAMES  FOR  STEEL  PASSENGER  CARS 

stiffened  vertically  by  the  window  posts  and  having  a  6  in.  by  6  in. 
by  %  in.  angle  at  the  bottom  and  an  equal  square  inch  section  of  metal 
at  the  belt  rail,  the  two  girders  having  a  square  inch  section  of  48  in 
all.  With  this  construction  a  substantial  body  bolster  is  essential,  as 
the  load  must  be  carried  at  the  bolster  extremities.  Usually  a  cast- 
steel  structure,  built  into  the  underframe  and  securely  riveted  to  it, 
is  used,  the  metal  may  thus  be  economically  distributed.  With  an 
underframe  of  this  type  there  is  no  trouble  due  to  difficulty  of  in- 
spection or  interference  with  attachment  for  axle  light  or  other 
equipment  under  the  car. 

9     The  fourth  type  (Fig.  4)  is  a  combination  of  types  &  and  c. 
Here  deep  center  sills  are  used,  having  a  square  inch  section  of,  say 


fflK 


T| 

I  i 
i  j 
i  ] 

y_y__ 


K—  -/6---H 


4n*r-*t 


FIG.  3     TYPE  c:  WEIGHT  CARRIED  BY  CAR  SIDES,  CENTER  SILLS  USED  ONLY  FOR 
BUFFING  AND  PULLING 


40  at  the  center  and  39  in  cast  steel  at  the  draw  gear.  The  side 
girders  have  a  square  inch  section  of  21  in  the  two.  Most  underframes 
of  this  type  now  in  service  are  built  with  cast-steel  end  portions  which 
include  in  one  casting  the  body  bolster,  platform,  side  and  center  sills 
extending  as  far  back  of  the  bolster  as  may  be  necessary  to  secure  a 
substantial  connection  to  the  center  sills  proper.  This  center  member 
we  do  not  consider  as  properly  constructed  for  the  reason  that  the 
section  is  unbalanced,  an  excess  of  metal  being  used  on  the  top. 
Heavier  angles  or  a  cover  plate  should  be  used  on  the  bottom,  which 
would  add  about  10  sq.  in.  or  more  of  metal. 

10  The  four  types  illustrated  are  of  underframes  actually  in 
service.  A  comparison  of  cross-sections  discloses  the  fact  that  no 
matter  from  what  angle  the  designer  has  approached  the  problem, 
approximately  the  same  square  inch  cross-section  has  resulted.  If, 
therefore,  any  one  type  has  an  advantage  in  weight  over  the  others, 


JOHN  MC  E.  AMES 


29 


it  must  be  attributed  to  difference  in  the  cross  members  of  the  under- 
frame. 

11     These   four   prevalent   types   have   been   recognized   by   the 
United  States  Government.     The  specifications  of  the  Postoffice  De- 
partment for  the  construction  of  steel  postal  cars  provide  as  follows: 
a  Heavy  center  sill  construction,  the  center  sills  acting  as  the 

main  carrying  member. 

b  .Side-carrying  construction,  the  sides  of  the  car  acting  as  the 
main  carrying  members,  having  their  support  at  the 
bolsters. 


Section  at  Center 

£-/.- -> 

K-//- 


.  Tim  V_ 

Section  at  Draft  Sill 
FIG.  4     TYPE  d:  WEIGHT  CARRIED  BOTH  BY  CENTER  SILLS  AND  CAR  SIDES 


c  Underframe  construction,  in  which  the  load  is  carried  by  all 
the  longitudinal  members  of  the  lower  frame.  The  super- 
structure shall  be  of  steel. 

d  Combination  construction  in  which  the  side  frames  carry  a 
part  of  the  load,  transferring  it  to  the  center  sills  at  points 
remote  from  the  center  plate  for  the  purpose  of  utilizing 
uniform  center  sill  area. 


30  UNDERFRAMES  FOR  STEEL  PASSENGER  CARS 

12  While  several  of  these  types  have  been  in  service  for  a  number 
of  years  the  required  time  has  not  passed  in  which  to  develop 
structural  defects  due  to  unseen  causes,  such  as  fatigue  of  metal, 
crystallization,  etc.  If  such  defects  exist  they  should  make  themselves 
known  during  the  next  three  or  four  years,  if  freight  construction 
is  any  criterion. 


No.  1388  d 

ROOF  STRUCTURE  FOR  STEEL  CARS 

BY  C.  A.  SELEY/  CHICAGO,  ILL. 
Non-Member 

Roofs  for  steel  passenger  equipment  cars  are  of  two  classes,  the 
clear-story  type  with  minor  variations  and  the  oval  type.  As  regards 
contour  and  general  appearance,  they  are  the  same  as  the  long  estab- 
lished standards  for  wooden  cars,  but  varied  as  to  constructive  detail, 
due  to  materials  employed. 

2  The  advent  of  the  steel  car  has  rather  encouraged  the  use  of 
the  oval  or  round  roof,  as  it  is  often  called,  particularly  for  cars  used 
for  baggage,  express,  and  postal  purposes.    It  is  cheaper  to  build  and 
maintain  and  fulfills  requirements  for  such  cars.    For  passenger  cars 
the  clear-story  type  prevails  very  generally,  as  it  assists  in  lighting  and 
ventilation  and  in  decorative  effect. 

3  The  framing  for  oval  roofs  consists  of  car  lines,  each  a  single 
member,  bent  to  the  shape  of  the  arch  and  extending  from  plate  to 
plate.     There  are  no  through  longitudinal  members  and  the  roof 
sheets  are  riveted  to  the  car  lines. 

4  Framing  of  clear-story  roofs  is  of  two  general  classes,  one 
employing  car  lines  of  one  piece  extending  from  plate  to  plate  and 
carrying  the  longitudinal  upper  deck  sills  and  plates,  and  the  other 
class  an  extension  of  the  side  framing  posts  as  far  as  the  upper  deck 
sill.    To  these  extensions  are  attached  a  member  which  comprises  deck 
posts  and  upper  deck  car  lines.     It  is  difficult  to  approximate  the 
strength  of  the  more  direct  lines  of  the  oval  roof  in  the  design  of  the 
clear-story  roof,  and  all  riveted  connections  must  be  thoroughly  con- 
sidered.   The  deck  sills  and  plates  are  through  members,  act  as  end 
stiffeners,  and  add  to  the  longitudinal  strength. 

5  The  shape  of  the  car  lines  of  either  type  of  roof  should  be  such 
as  to  facilitate  fastening  of  roof  and  of  the  inner  ceiling  or  finish, 
and  between  these  there  should  be  a  generous  amount  of  insulating 
material  to  intercept  the  heat  of  summer  and  the  cold  of  winter. 

6  The  committee  of  engineers  who  framed  the  specification  for 
Mechanical  Engineer,  Eock  Island  Lines. 

Presented  at  the  New  York  Meeting,  April  1913,  of  THE  AMERICAN  SO- 
CIETY OF  MECHANICAL  ENGINEERS. 

31 


32  ROOF  STRUCTURE  FOR  STEEL  CARS 

full  postal  car  construction,  which  was  approved  by  the  Postoffice  De- 
partment in  March  1912,  contains  the  following  paragraphs  in  regard 
to  the  roofs  of  such  cars  and  is  probably  as  authoritative  a  statement 
as  there  is  available.  The  strength  of  roofs  of  some  cars  that  have 
been  rolled  over  in  accidents  has  been  checked  against  the  formula 
used,  and  it  has  been  found  ample  to  afford  support  against  serious 
roof  distortion  in  such  cases. 

7  The  postal  specification  reads  as  follows : 

ROOF 

' '  General 

The  roof  may  be  of  either  the  clear-story  or  turtle-back  type,  depending 
on  the  standard  contour  of  the  railroad  for  whose  service  the  cars  are  built. 
In  the  clear-story  type,  the  deck  plates  shall  be  in  the  form  of  a  continuous 
plate  girder,  extending  from  upper-deck  eaves  to  deck  sill,  and  either  built  up 
of  pressed  or  rolled  shapes  or  pressed  in  one  piece  from  steel  plates.  The  car 
lines  may  be  either  rolled  or  pressed  steel  shapes,  extending  in  one  length  across 
car  from  side  plate  to  side  plate,  or  may  extend  only  across  upper  deck.  In  the 
latter  case  the  lower  deck  carlines  may  be  formed  by  cantilever  extensions  of 
the  side  posts  or  by  independent  members  of  pressed  or  rolled  shapes.  In  the 
turtle-back  type,  the  car  lines  may  be  of  either  pressed  or  rolled  shapes,  extend- 
ing in  one  length  across  car  between  side  plate  and  side  plate,  or  may  consist 
of  cantilever  extensions  of  the  posts. 
' '  Car  Lines 

The  projected  area  of  the  portion  of  roof  in  square  feet,  supported  by  car 
lines,  divided  by  the  sum  of  the  section  moduli  of  the  carlines,  must  not  be 
more  than  100. 
' '  Eoof  Sheets 

Roof  sheets,  if  of  steel  or  iron,  shall  be  of  a  minimum  thickness  of  0.05 
inches,  and  either  riveted  or  welded  at  their  edges." 

8  The  design  of  the  roof  is  also  subject  to  the  general  paragraphs 
on  stresses  and  details  of  the  postal  car  specification. 

9  There  are  several  bills  in  Congress  having  in  view  the  substi- 
tution of  steel  passenger  equipment  on  railroads  for  present  wooden 
cars.     Should  any  of  these  become  law,  specifications  for  construction 
will  be  necessary,  and,  as  the  postal  car  specification  has  been  ap- 
proved and  adopted  as  standard  by  the  Government,  no  doubt  this 
specification  will  be  used  as  a  basis  in  determining  the  requirements 
for  other  steel  passenger  equipment  cars,  not  only  for  the  roofs,  but 
for  the  other  features  of  construction. 


No.  1388  e 

SUSPENSION  OF  STEEL  CARS 

BY  E.  W.  SUMMERS/  PITTSBURGH,  PA. 
Non-Member 

If  we  could  operate  steel  cars  over  rails  having  no  kinks,  curves 
or  irregularities  in  their  alignment,  in  other  words,  over  an  absolutely 
straight  track,  there  would  be  little  need  of  springs  or  other  devices 
for  flexible  support. 

2  Unfortunately  the  roadways  we  have  to  contend  with  cannot 
be  made  or  maintained  in  true  alignment.     Frost  and  water  make 
constant  changes  in  the  track  support.     Lateral  curvature  requires 
super-elevation  of  the  outer  rail.     In  passing  from  a  tangent  to  a 
curve,  or  vice  versa,  the  tracks  under  one  truck  are  in  wind  with  those 
under  the  other  one,  sometimes  as  much  as  4  or  5  in.  depending  upon 
the  degree  of  curvature  and  the  length  of  the  car. 

3  iSteel  car  bodies  of  the  enclosed  type,  such  as  box  cars,  mail, 
baggage,  or  passenger  coaches,  are  of  rigid  construction  and  have 
high  torsional  resistance.     A  three-legged  stool  on  an  irregular  floor 
surface  will  stand  upon  all  of  its  legs  while  one  having  four  legs  may 
carry  all  of  its  load  upon  two  diagonal  supports. 

4  The  use  of  truck  springs  helps  the  illusion  that  we  are  dis- 
tributing the  car  body  load  on  a.11  of  the  wheels.    The  uneven  deflec- 
tion of  the  springs  indicates  directly  the  increased  load  of  one  spring 
over  the  other.     When  the  track  surface  is  warped  more  than  the 
total  spring  travel,  the  whole  load  is  carried  at  two  diagonal  corners, 
tending  to  twist  the  car  body.     This  twisting  tendency  is  constantly 
changing,  first  in  one  direction  and  then  in  the  other,  as  the  super- 
elevated  rail  changes  from  one  side  of  the  track  to  the  other.     The 
effect  upon  wooden  passenger  cars  is  to  work  the  joints  loose  and  cause 
them  to  screech  and  grind  like  the  spokes  of  a  wooden  wagon  wheel  in 
hot  dry  weather. 

5  The  side  bearings  of  steel  sleeping  cars  pop  like  sledge  hammer 
blows  when  the  car  is  taking  or  leaving  a  curve.    The  slight  twist  in 
the  track  surface  throwing  excessive  load  upon  two  diagonal  corners 

'President,  Summers  Steel  Car  Company. 

Presented  at  the  New  York  Meeting,  April  1913,  of  THE  AMERICAN  SO- 
CIETY OF  MECHANICAL  ENGINEERS. 

33 


34  SUSPENSION  OF  STEEL  CARS 

of  the  car  causes  the  bearings  to  grip  and  adhere  to  each  other  coin- 
cident with  the  slewing  of  the  truck.  "When  the  twisting  of  the  truck 
exceeds  the  play  in  the  parts  around  the  truck  bolster  the  side  bearings 
let  loose  and  jump  with  resulting  hammer  blows.  .  More  efficient 
roller  side  bearings  may  prevent  the  gripping  and  jumping,  but  the 
uneven  load  is  still  present.  The  twisting  effect  upon  the  car  body  is 
not  removed. 

6  Failure  in  roofs  of  wooden  box  cars  and  the  resulting  damage 
to  merchandise  in  transit  is  due  to  this  constant  twist.    Eoof  designers 
have  attempted  to  remedy  this  by  making  the  roof  flexible  and  with 
slip  joints.     To  be  consistent  they  should  go  further  and  make  the 
whole  car  of  india  rubber.    A  practical  construction  for  the  enclosed 
type  of  steel  car  bodies  must  and  always  will  be  rigid  and  of  high 
torsional  resistance. 

7  .The  necessity  for  flexibility  between  the  car  body  and  the 
trucks,  and  for  an  even  distribution  of  the  load  upon  all  of  the  wheels 
seems  not  to  be  fully  appreciated  as  yet,  but  with  each  succeeding  year 
wrecks  due  to  broken  rails,  wheels  and  truck  structure  will  drive  this 
home.     Suspension  of  steel  cars,  as  has  been  developed  by  the  writer 
in  the  past  three  years,  does  permit  of  a  more  even  distribution  of  the 
load  upon  the  wheels  than  with  center-bearing  trucks. 

8  Fig.  1  is  an  illustration  of  a  cross-section  through  an  engine 
tender  at  the  center  of  one  of  the  trucks.    It  illustrates  the  method 
of  suspension  referred  to  and  is  applicable  to  any  kind  of  car. 

9  The  inclined  hangers  a,  the  cradle  ~b,  and  the  side  rockers  c 
are  shown  heavily  shaded.     There  are  two  inclined  hangers  at  each 
side  of  each  truck.     A  heavy  rectangular  bar  extends  through  the 
lower  ends  of  the  hangers  a.    A  cast-steel  bracket,  which  is  part  of  the 
car  underframe,  rests  upon  each  end  of  the  rectangular  bar.     The 
upper  ends  of  inclined  hangers  a  are  supported  upon  the  outer  end  of 
the  cradle  which  rests  upon  the  segmental  rocker  c  and  transmits  the 
car  body  load  directly  into  the  truck  side  frame.    The  lower  ends  of 
hangers  a  are  maintained  a  fixed  distance  apart  transversely  of  the 
car,  by  reason  of  the  brackets  d  being  a  fixed  part  of  the  car  under- 
frame.     Their  upper  ends  are  held  at  a  fixed  transverse  distance  by 
their  connection  with  the  cradle  &.    Both  the  upper  and  lower  ends 
of  bars  a  are  pivotally  connected  with  rolling  contact. 

10  With  one  end  of  a  car  on  level  track  and  the  other  end  having 
one  rail  at  a  higher  elevation,  the  tendency  will  be  for  the  high  rail 
to  carry  all  of  the  load  at  that  end  of  the  car,  or  to  have  the  car  sup- 
port taken  at  two  of  its  diagonal  corners. 


E.  W.  SUMMERS 


35 


11  With  inclined  hanger  suspension  the  car  will  swing  sideways, 
the  hangers  at  the  high  rail  swinging  inward  and  downward,  while 
the  ones  at  the  other  end  of  the  cradle  swing  outward  and  upward, 
picking  up  the  load  at  the  low  rail  and  maintaining  its  distribution 
on  all  of  the  wheels  much  the  same  as  if  suspended  by  two  bars  from 


FIG.  1     CROSS-SECTION  OF  ENGINE  TENDER  AT  CENTER  OF  ONE  OF  TRUCKS 


a  point  0  at  the  intersection  of  the  center  line  of  the  inclined  hangers 
extended.  The  load  or  rigid  car  body  will  find  its  own  position  verti- 
cally under  this  common  point  of  support  0,  each  of  the  extended  sus- 
pension bars  taking  its  share  of  the  load. 


36  SUSPENSION  OF  STEEL  CAKS 

13  The  slight  warping  of  the  track  surface,  which  causes  all  of 
the  load  to  be  carried  on  half  of  the  wheels  at  two  diagonal  corners  of 
a  rigid  car  body  with  the  ordinary  center-bearing  truck,  is  corrected 
by  the  short  inclined  suspension  bars  a,  practically  the  same  as  if  the 
suspension  was  from  point  0. 

13  It  is  the  inclination  of  these  bars  that  makes  vertical  adjust- 
ment possible,  one  bar  swinging  inward  and  downward,  the  other 
swinging  outward  and  upward  at  one  end  of  the  car,  the  bars  at  the 
other  end  swinging  in  the  opposite  direction,  the  car  body  finding  its 
position  much  the  same  as  a  boat  does  in  water. 

14  Imagine  the  bars  a  at  one  end  of  a  car  swung  to  the  left,  as 
shown  in  the  unshaded  dotted  position,  and  at  the  other  end  swung 
to  the  right  an  equal  amount:  this  makes  correction  for  a  warped 
track  surface  of  about  8  in.  in  the  length  of  a  car.     Or,  imagine  the 
hangers  a  swung  to  the  left  at  both  ends  of  the  car,  as  shown  in  the 
dotted  position:  this  is  the  inclination  the  car  body  will  assume  in 
rounding  a  sharp  curve  at  high  velocity,  the  top  of  the  car  leaning 
inward  and  the  bottom  swinging  outward,  the  position  assumed  by  a 
bicycle  rider  in  rounding  a  curve. 

15  The  cradle  b  is  pivoted  about  a  vertical  axis  on  the  king  pin  e 
and  can  also  have  movement  transversely  of  the  car,  this  movement 
being  limited  by  the  action  of  springs  /.    On  account  of  the  inertia  of 
the  car  body  and  its  load,  the  cradle  moves  transversely  of  the  car, 
rotating  the  hangers  about  their  lower  ends  when  rough  track  is  en- 
countered at  high  speed.    Without  this  cradle  movement,  the  inclined 
hangers  are  impracticable;  with  it,  the  car  body  movement  is  without 
jar  or  jerk  and  we  have  perfect  adjustment  for  all  track  conditions. 

16  The  car  body  is  carried  at  each  side  almost  directly  under  its 
rigid  side  girders,  which  by  position  have  great  depth  and  can  carry 
the  load  with  the  least  deflection.     Floor  beams  may  be  made  con- 
tinuous from  side  to  side  of  the  car.     The  necessary  buffing  and 
tugging  column  may  be  disposed  with  its  web  in  a  horizontal  position 
under  the  transverse  beams,  greatly  simplifying  the  car  framing. 

17  With  the  advent  of  steel  construction  for  enclosed  cars  a  rigid 
structure  came  into  use,  one  that  cannot  be  handled  over  rough  track 
as  we.  have  been  handling  the  spongy  wooden  structure.     There  may 
be  much  hewing  and  chopping  into  old  methods  before  the  necessary 
compromise  is  made  between  the  rigid  car  body  and  the  changeable 
track  surface,  but  why  not  do  it  all  at  once,  and  stop  fooling  with 
dynamite  ? 


No.  1388  / 

SIX-WHEEL  TRUCKS  FOR  PASSENGER 

CARS 

BY  JOHN  A.  PILCHER,  EOANOKE,  VA. 
Member  of  the  Society 

Consideration  of  the  subject  of  trucks  for  steel  passenger  cars  is 
practically  a  consideration  of  trucks  for  any  passenger  car,  the  primary 
thought  being  that  steel  passenger  cars  should  have  steel  trucks  to 
prevent  the  possibility  of  fire,  and  also  because  of  their  great  weight, 
metal  is  the  most  suitable  material  for  strength  and  durability  that 
can  be  used  in  the  limited  space  available  for  the  truck.  The  fire 
damage  from  a  wooden  frame  truck  could  not  be  serious  on  a  steel 
car,  and  there  are  wooden  cars  equally  as  heavy  as  the  general  run  of 
steel  cars ;  the  writer  having  one  in  mind  in  the  construction  of  which 
the  sills  were  plated  with  8-in.  channels,  weighing  17&,700  Ib.  A 
few  steel  cars  weigh  as  much  as  this,  but  we  have  no  record  of  any 
weighing  more.  However,  for  steel  passenger  cars  we  will  consider 
only  the  all-steel  truck. 

2  Practice  of  the  past  brings  to  our  attention  the  pedestal  type 
of  passenger  truck  construction  both  for  four-wheel  and  six- wheel 
trucks,  the  general  characteristics  of  both  being  identical.     The  six- 
wheel  truck  "with  the  same  size  axle  is,  of  course,  capable  of  greater 
load  and  also  of  transmitting  to  the  car  the  track  irregularities  to  a 
less  extent,  because  the  results  of  the  irregularities  are  modified  by 
the  system  of  equalization.    In  the  six-wheel  truck  the  location  of  the 
equalizer  springs  is  fixed  at  a  definite  point  between  the  wheels. 

3  While  the  details  of  these  two  trucks   differ  slightly,  their 
functions  are  practically  identical.     Both  trucks  have  been  used  for 
a  considerable  length  of  time,  but  the  four-wheel  truck  was  evidently 
developed  first  and  its  necessary  functions,  determined  by  experience, 
were  later  incorporated  in  the  design  of  the  six- wheel  truck,  which  was 
probably  first  brought  about  by  the  increased  loads. 

4  Except  for  the  especially  constructed  truck  used  by  the  Penn- 
sylvania Railroad  and  one  other,  which  we  understand  has  been  de- 
signed, these  are  the  only  regular  types  of  trucks  available. 


Presented  at  the  New  York  Meeting,  April  1913,  of  THE  AMERICAN  SO- 
CIETY OF  MECHANICAL  ENGINEERS. 

37 


38  SIX-WHEEL  TRUCKS  FOR  PASSENGER  CARS 

5  Wheels.     For  passenger  service,  the  wheels  have  been  prac- 
tically narrowed  down  to  steel  tired  wheels  and  wrought-steel  wheels. 
The  steel  tired  wheels  have  been  of  many  forms  of  centers  and 
fastenings;    the   latest   recommended   practice    of   the   Master    Car 
Builders'  Association  is  that  the  tire  be  shrunk  on  and  bolted.    The 
recent  development  of  the  solid  wrought-steel  wheel  has  made  avail- 
able for  passenger  car  service  a  wheel  equally  as  safe  and  durable  as 
the  steel  tired  wheel  at  a  very  much  reduced  cost.    The  Master  Car 
Builders'  recommendations  recognize  both  the  36-in.  and  38-in.  size 
in  this  wheel  for  passenger  service,  the  36-in.,  however,  being  the 
most  generally  used.     These  wheels,  if  carefully  turned,  should  give 
as  satisfactory  service  as  any  wheels  available. 

6  Axles.     The  standards  of  the  Master  Car  Builders'  Association 
gives  the  choice  of  selection  of  four  sizes  of  axles : 

Size  of  Journal  Axle  Load,  Lb. 

3%  in.  x     7  in..  . 15,000 

4%    "  x     8    » 22,000 

5        "  x     9    " 31,000 

5V2    "  x  10    " 38,000 

7  They  also  offer  an  axle  as  recommended  practice  with  6  in.  by 
11  in.  journals  for  50,000-lb.  axle  load.     These  loads,  however,  are 
for  freight  service;  for  passenger  service  we  would  recommend  the 
use  of  from  60  per  cent  to  75  per  cent  of  the  loads  used  in  freight 
service,  based  on  the  light  weight  of  the  car,  and  limiting  the  load  to 
about  90  per  cent  of  that  in  freight  service,  considering  the  weight  of 
both  car  and  lading.    The  lighter  rating  is,  of  course,  to  be  taken  for 
cars  such  as  baggage  and  express,  since  the  increased  weight  on  ac- 
count of  lading  would  be  heavier,  while  the  higher  rating  could  be 
taken  for  coaches  and  similar  cars  where  the  increase  of  the  lading 
would  be  light.     Table  1  gives  the  sizes  of  axles,  and  relative  light 
weights  of  cars  on  this  basis. 

8  The  Postoffice  Department  has  limited  the  maximum  load  per 
wheel  for  postal  cars  to  15,000  Ib.  when  using  5%  in.  by  9  in.  journals, 
and  to  18,000  Ib.  when  using  5  in.  by  10  in.  journals,  making  a 
further  limitation  based  upon  18,000  Ib.  as  the  maximum  brake  load 
for  any  one  cast-iron  brake  shoe  under  emergency  conditions  of  brake 
application.     This  limitation  of  wheel  loads,   after   deducting  the 
weights  of  the  wheels  and  axles,  allows  a  pressure  of  304  Ib.  per  sq.  in. 
projected  area  on  the  5  in.  by  9  in.  journals,  and  300  Ib.  per  sq.  in. 
projected  area  on  the  5%  in.  by  10  in.  journals,  also  a  pressure  of  15-22 


JOHN  A.  PILCHER  39 

lb.  per  lineal  in.  on  the  5  in.  by  9  in.  journals,  and  1665  Ib.  per  lineal 
in.  on  the  5%  in.  by  10  in.  journals,  and  from  the  experience  that 
some  roads  have  had  these  seem  to  be  just  as  high  as  should  be 
allowed. 

TABLE  1     SIZE  OF  AXLES  AND  WEIGHT  OF  LIGHT  CARS 


Axles,  In. 

Four  -Wheel  Trucks,  Lb. 

Six-Wheel  Trucks,  Lb. 

3^  x   7 
4&  x   8 
5x9 
5^  xlO. 

40,000  to    52,000 
52,000  to     72,000 
72,000  to  100,000 
100,000  to  120,000 

60,000  to     78,000 
78,000  to  108,000 
108,000  to  150,000 
150,000  to  180,000 

9  Boxes  and  Contained  Parts.  The  Master  Car  Builders'  Associa- 
tion has  provided  standard  passenger  boxes  for  axles  with  3  %  in.  by 
7  in.,  4  %  in.  by  8  in.,  and  5  in  by  9  in.  journals.     For  the  5  y2  in. 
by  10  in.  journal,  which  is  often  in  use,  they  have  not  yet  established 
recommended  practices,  but  the  previous  designs  are  having  their  in- 
fluence on  the  shape  of  the  box  for  this  journal. 

10  Pedestals.    Cast-iron  pedestals  seem  to  be  usually  the  accepted 
material,  and  the  Master  Car  Builders'  Association  has  also  provided 
standards  to  suit  the  boxes. 

11  Equalizer  Springs.     These  are  four  in  number  on  both  the 
four-wheel  and  six-wheel  trucks,  and  while  necessarily  provided  with 
a  limited  amount  of  deflection,  they  relieve  the  heavy  truck  frames  of 
shock,  and  on  six-wheel  trucks  provide  the  points  of  support  for  the 
proper  equalization. 

12  Wheel  Pieces  or  Side  Frames  with  Transoms  or  Cross  Ties. 
These  constitute  the  truck  frame  to  hold  the  other  parts  in  their 
relative  position,  and  at  the  same  time  transfer  the  load  from  the 
bolster  hangers  to  the  equalizer  springs.    Being  structures  supported 
at  four  points,  they  necessarily  have  to  be  supported  on  springs  to 
prevent  excessive  stresses  due  to  any  variations  in  the  height  of  these 
four  points.     As  an  illustration,  when  the  truck  on  a  tangent  is  ap- 
proaching a  curve  the  rise  of  the  outer  rail  is  about  1  in.  in  50  ft. 
This  will  raise  one  of  these  four  points  above  the  plane  passed  through 
the  other  three,  and,  while  the  difference  is  small  in  the  short  length 
of  the  truck,  the  irregularity  has  to  be  taken  up  by  the  springs,  other- 
wise the  truck  frame  would  be  similar  to  a  four-legged  table  with  one 
high  leg. 


40  SIX-WHEEL  TRUCKS  FOR  PASSENGER  CARS 

13  When  we  consider  the  case  of  a  derailment  where  one  wheel 
of  the  truck,  whether  four-wheel  or  six- wheel,  falls  into  a  deep  hole, 
or  drops  from  a  high  rail,  we  find  this  condition  exaggerated  to  such 
an  extent  that  the  whole  load  will  be  supported  on  two  points.    Then 
unless  the  structure  is  sufficiently  flexible  to  follow,  it  will  necessarily 
have  to  be  strong  enough  to  resist  this  abnormal  load. 

14  The  calculation  of  the  stresses  under  such  uncertain  con- 
ditions of  loading  is  certainly  a  very   complex  problem.     It  is   a 
pertinent  question  whether  or  not  the  designers  should  undertake  to 
care  for  such  an  abnormal  condition. 

15  Bolster  Hangers.     The  lateral  movement  of  the  bolster,  one 
of  the  very  necessary  features  of  a  passenger  truck,  is  usually  ac- 
complished by  the  use  of  swinging  hangers.     This  movement  should 
be  limited  to  from  1%  in.  to  1%  in.  each  side  of  the  center,  and  in 
placing  this  limit  arrangement  should  be  made  so  that  the  stop  will 
not  be  abrupt.     This  is  ordinarily  accomplished  by  the  use  of  short 
hangers,  or  when  long  hangers  are  used  by  the  addition  of  lateral 
motion    springs,    either    of    which    offers    an    increasing   resistance. 
Rollers  on  cylindrical  or  curved  plains  can  produce  the  identical 
movement  made  by  the  short  hangers. 

16  Bolster.     On  the  four-wheel   truck  the  bolster  is  a  simple 
beam,  but  on  the  six-wheel  truck  we  have  a  more  complex  structure 
resting  on  four  points  of  support.    This  condition  brings  up  the  same 
complex  problem  referred  to  in  connection  with  the  truck  frame  sup- 
ported on  four  points,  except  that  it  rests  on  much  more  flexible 
springs  than  does  the  truck  frame.    These  springs  can  hardly  be  ex- 
pected to  take  up  all  of  the  variations  in  elevation  that  will  likely  be 
met  with  in  case  of  a  partial  derailment.     The  same  question  as  to 
whether  or  not  the  designer  should  allow  for  such  abnormal  conditions 
is  again  raised. 

17  Center  Plate.    The  usually  accepted  center  plate  for  passenger 
cars  is  of  the  spherical  pattern,  allowing  more  perfect  adjustment, 
and  more  even  distribution  of  weights  than  can  be  obtained  from  the 
flat  bottom  center  plate,  but  making  necessary  close  and  accurate  ad- 
justment of  the  side  bearings  to  prevent  the  rocking  movement  be- 
tween the  car  body  bolster  and  the  truck  bolster. 

18  The  f rictionless  center  plate  would  of  course  be  very  desirable, 
but  conical  rollers  and  balls  of  sufficient  number,  of  the  size  that  can 
be  put  in  the  available  space,  seem  not  to  have  been  as  successful  as 


JOHN  A.  PILCHER  41 

could  be  wished.     The  ingenious  designer  is  still  at  work  on  this 
particular  problem. 

19  Side  Bearings.    Side  bearings  must  be  made  so  that  they  can 
be  readily  kept  adjusted  to  reduce  to  a  minimum  the  rocking  move- 
ment between  the  car  body  bolster  and  the  truck  bolster,  and  in  this 
way  confine  the  oscillation  of  the  car  to  the  variation  in  the  deflection 
of  the  springs  on  either  side. 

20  The  relative  location  of  the  side  bearings,  each  side  of  the 
center,  is  a  question  often  discussed.     In  passenger  cars  the  practice 
generally  is  to  place  them  at  as  great  a  distance  from  the  center  as 
practical.     This  in  our  judgment  is  correct,  and  of  particular  ad- 
vantage in  the  case  of  frictionless  or  roller  side  bearings. 

21  Where  the  side  bearings  are  in  actual  contact  and  the  bolsters 
are  rigid,  the  oscillation  of  the  car  is  controlled  entirely  by  the  differ- 
ence in  deflection  of  the  springs  on  either  side,  so  that  if  the  side 
bearing  is  set  out  sufficiently  far  to  prevent  the  car  body  upsetting  on 
the  truck,  it  serves  its  purpose  in  preventing  car  oscillation  as  well 
there  as  at  any  other  location. 

22  For  the  same  type  of  side  bearing,  it  oilers  just  as  much,  but 
no  more,  resistance  to  turning  than  if  located  far  from  the  center, 
because  as  the  lever  arm  is  increased  the  pressure  is  reduced  in  like 
proportion. 

,23  When  the  car  on  a  tangent  is  approaching  a  curve,  the  rise 
of  the  track  on  the  outer  rail  tends  to  bring  a  pressure  on  the  side 
bearing  of  the  leading  truck,  next  the  outside  of  the  curve,  and  on  the 
side  bearing  of  the  trailing  truck  toward  the  inside  of  the  curve. 
Where  the  side  bearings  are  in  contact  this  variation  in  elevation  has 
to  be  taken  care  of  by  the  deflection  of  the  springs  which  have  to  deflect 
the  same  amount  whether  the  load  is  exerted  on  the  bolster,  at  a  point 
near  the  center,  or  far  away  from  the  center.  If  the  load  comes  far 
from  the  center  it  takes  much  less  pressure  to  influence  the  deflection 
of  the  springs.  This  would  be  to  the  decided  advantage  of  the  side 
bearings,  particularly  in  the  case  of  the  frictionless  side  bearing,  in 
preventing  wear  and  would  also,  to  a  more  limited  extent,  be  of  ad- 
vantage to  the  ordinary  flat  side  bearing. 

24  Brakes.  On  passenger  cars,  the  pressure  on  the  brake  shoes 
approximates  the  loads  on  the  wheels.  Particularly  is  this  the  case 
of  coaches  where  the  lading  is  only  a  small  proportion  of  the  total 
weight.  In  some  braking  arrangements  the  brake  shoe  load  is  even 
greater  under  certain  conditions  than  the  wheel  load;  therefore  the 
lighter  the  wheel  loads  the  better  for  the  brakes.  This  is  a  decided 


42  SIX-WHEEL  TEUCKS  FOR  PASSENGER  CARS 

argument  in  favor  of  the  six- wheel  trucks  for  heavy  cars,  and  an  argu- 
ment against  the  use  of  four-wheel  trucks  under  heavy  passenger  cars, 
even  though  the  weights  can  be  readily  sustained  by  the  use  of  suffi- 
ciently large  axles. 

25  The  application  of  the  brakes  to  the  six-wheel  trucks  in  such 
a  manner  as  to  allow  for  the  adjustment  of  worn  shoes  and  worn 
wheels  is  a  very  difficult  task  on  account  of  the  limited  space  available. 
It  is  almost  impossible  to  accomplish  this  task  with  the  use  of  wheels 
less  than  36  in.  in  diameter. 

26  Six-Wheel  Trucks.    Since  steel  cars  are  of  recent  construction, 
and  recent  conditions  have  generally  called  for  large  cars,  the  weight 
is  almost  always  great.    The  six-wheel,  all-metal  truck  has  the  follow- 
ing advantages  which  make  for  its  selection  over  other  types : 

a  It  is  non-inflammable. 

b  It  provides  a  strong  material  to  resist  the  heavy  loads,  and 
occupies  only  a  limited  space. 

c  It  provides  a  durable  material. 

d  It  reduces  the  axle  loads,  and  the  unit  load  on  the  bearings, 
lessening  the  liability  to  hot  boxes,  reducing  the  pressure 
on  the  brake  shoes,  lessening  the  tendency  to  heat  the 
wheels  and  shoes,  adding  to  the  life  of  the  brake  shoes,  and 
reducing  the  frequency  between  renewals  and  adjustments. 

e  It  spreads  the  heavier  loads  over  a  greater  area  of  structures, 
and  brings  more  points  of  contact  with  the  rail,  reducing 
the  influence  of  track  irregularities  on  the  riding  of  the 
car,  and  in  cases  of  very  heavy  cars,  where  the  unit  pres- 
sure between  wheel  and  rail  might  approximate  the 
elastic  limit,  reduces  the  tendency  to  shell  the  wheel  and 
roll  out  the  rail,  adding  to  the  life  of  both. 

27  It  has  been  estimated  that  for  a  passenger  car  making  50,000 
miles  per  year,  the  cost  for  hauling  the  car  is  5  cents  per  Ib.  per  year. 
If  the  six-wheel  trucks  weigh  14,000  Ib.  per  car  more  than  the  four- 
wheel  trucks  necessary  to  carry  the  same  car,  it  means  the  hauling  of 
14,000  Ib.  additional  at  a  cost  of  $700  per  year,  which  brings  up  a 
question  for  vital  consideration. 

28  While  the  wheels,  brasses,  and  brake  shoes,  and  other  such 
removable  parts  may  individually  have  a  longer  life,  there  are  also 
more  of  them  in  service  during  the  period.    Careful  comparison  would 
have  to  be  made  to  determine  which  has  the  advantage  at  this  point. 


JOHN  A.  PILCHER  43 

29  Four-wheel  Trucks.     The  four-wheel,  all-metal  truck  is  also 
available  in  connection  with  steel  cars,  and  has  the  advantage  of 
reduced  first  cost,  reduced  weight,  smaller  number  of  parts  to  main- 
tain, and  if  the  car  is  sufficiently  light  for  the  unit  stress  between  the 
rail  and  wheel  to  be  kept  down  to  a  point  well  below  the  elastic  limit 
of  the  material,  they  should  be  given  serious  consideration.    The  only 
drawback  under  these  conditions  is  the  possibility  of  its  reduced  riding 
qualities.    Its  decided  advantage  in  reducing  the  weight  of  the  train 
should  help  to  make  it  a  favorite  because  of  the  corresponding  reduc- 
tion in  the  cost  of  transportation. 

30  Cast-Steel  vs.  Riveted  Wrought-Steel  Frames.    The  introduc- 
tion of  heavy  passenger  equipment  is  rapidly  doing  away  with  both 
the  four-wheel  and  six-wheel  wooden  frame  trucks.     The  reduced  cost 
of  maintenance  amply  justifies  this  change  if  our  information  is  cor- 
rect.    Cast-steel  one-piece  frames,  and  riveted  wrou^ht-steel  frames 
of  various  cross-sections  have  been  worked  out  and  are  now  in  use; 
both  are  reported  as  giving  satisfactory  service,  but  figures  showing 
the  exact  relative  cost  of  maintenance  are  not  available. 

31  The  cast-steel  one-piece  frame  has  become  a  great  favorite 
even  in  the  face  of  the  high  unit  cost  of  these  particular  castings. 
The  adaptability  of  the  castings  to  the  various  changes  of  form  and 
section  necessary  on  account  of  the  limited  available  space  has  no 
doubt   had   much   influence.      The    attractiveness   of   the   one-piece 
structure,  eliminating  all  joints,  and  furnishing  a  frame  ready  set  up, 
is  another  strong  argument  in  its  favor.     The  manufacturers  having 
control  of  this  cast-steel  truck  frame  have  evidently  been  successful 
in  reducing  to  a  minimum  the  concealed  flaws  often  met  with  in  steel 
castings.     This,  no  doubt,  has  added  largely  to  its  popularity. 

33  While  the  absence  of  riveted  joints  and  the  consequent 
doubling  of  material  at  the  joints,  helps  to  keep  down  the  weight,  the 
fact  that  the  working  fiber  stress  of  cast  steel  is  taken  low,  and  the 
sections  at  many  points  have  to  be  made  larger  than  is  necessary  on 
account  of  foundry  limitation,  the  weight  of  the  frame  as  a  whole  is 
great.  This  added  to  the  large  unit  cost  for  special  steel  castings 
makes  the  user  pay  well  for  the  advantages  gained. 

33  The  riveted  wrought-steel  frame  seems  to  have  been  held  back 
in  its  development  by  the  success  of  its  rival  in  cast  steel.  Many 
users  have  shown  conservatism  in  making  use  of  the  good  thing  already 
considered  acceptable,  hesitating  to  try  out  the  different  construction 
with  the  hope  of  lower  first  cost,  with  less  weight,  and  equally  good 
service. 


44  SIX-WHEEL  TRUCKS  FOR  PASSENGER  CARS 

34  Wrought  steel  at  a  very  moderate  unit  cost  has  the  advantage 
of  being  a  very  reliable  material  which  can  be  worked  to  a  relatively 
high  fiber  stress.     The  cost  of  fabrication,  when  the  work  is  done  in 
any  large  quantity,  when  added  to  the  cost  of  material,  will  still  leave 
a  large  margin  in  its  favor.    Is  it  possible  that  the  lack  of  an  especially 
interested  advocate  has  prevented  its  virtues  from  becoming  prominent, 
and  delayed  the  experience  needed  to  prove,  in  actual  service,  its  worth  ? 

35  We  find  that  practically  all  of  the  prominent  car  builders 
have  already  worked  up  designs  for  wrought-steel  trucks,  and  are 
ready  to  construct  them  if  the  purchaser  so  desires,  but  they  do  not 
seem  inclined  to  push  them,  as  they  evidently  offer  no  special  induce- 
ment to  their  own  advantage.    Only  a  few  have  been  built  and  placed 
under  cars  by  them,  and  in  some  cases  none,  but  from  what  I  have  been 
able  to  find  out  they  have  confidence  in  them. 

36  I  find  several  railroad  companies  building  and  using  both 
four  and  six-wheel  trucks,  of  the  usual  type  of  construction,  with 
riveted  wrought-steel  frames,  and  from  all  reports  they  are  giving 
satisfaction. 

37  Another  prominent  railroad  is  using  both  four  and  six- wheel 
trucks,  of  a  form  of  construction  differing  from  the  ordinary  type, 
built  of  riveted  wrought  steel.     As  a  large  number  of  these  are  in 
daily  evidence,  and  are  constantly  being  built  by  them,  they  must 
be  proving  the  worth  of  the  riveted  wrought-steel  construction,  as  well 
as  that  of  the  special  type  of  construction. 

38  Experience  of  several  years  and  careful  comparison  of  the  cost 
of  maintenance  will  be  needed  to  say  whether  the  one-piece  cast-steel 
frame,  or  the  riveted  wrought-steel  frame  truck  will  be  the  most  advan- 
tageous, when  both  the  first  cost  and  weight  are  considered  along  with 
the  cost  of  maintenance. 

39  Variety  of  choice  offers  an  opportunity  for  discussion.    In  the 
hope  of  bringing  out  this  discussion  we  advocate  for  steel  passenger 
cars:     (a)  iSix- wheel  truck;  (b)  the  riveted  wrought  steel  frame;  (c) 
the  use  of  the  Master  Car  Builders  standard  axles,  boxes  and  parts,  and 
pedestals;  (d)  36-in.  wrought-steel  wheels. 


No.  1388  g 

STEEL  INTERIOR  FINISH  FOR  STEEL 
PASSENGER  CARS 

BY  FELIX  Keen,1  MCKEES  EOCKS,  PA. 
Non-Member 

Every  one  who  has  followed  the  progress  in  steel  passenger  car 
construction  during  the  last  ten  years,  which  is  about  the  age  of  the 
oldest  steel  passenger  car,  has  noticed  that  very  little,  if  any  steel  was 
used  in  the  interior  finish  until  within  the  last  four  or  five  years. 

2  The  first  attempt  to  use  steel  in  passenger  cars  resulted  in 
steel  underframes  with  wood  superstructure.     The  next  development 
provided  steel  underframe  and  steel  superstructure,  but  with  wooden 
roof  and  wood  interior  finish.     Further  developments  eliminated  the 
wooden  roof  and  the  final  efforts  produced  an  all  steel  car.    Consider- 
ing that  this  development  was  made  during  a  period  of  four  years, 
the  results  obtained  are,  to  say  the  least,  highly  gratifying. 

3  The  earlier  designs  of  steel  cars  with  steel  interior  finish  are 
sometimes  called  all  steel  cars,  leaving  the  impression  that  they  are 
fireproof  in  every  respect,  but  this  is  not  correct  because  too  much 
wood  was  used  in  the  form  of  wood  furrings  to  enable  the  application 
of  the  steel  finish  with  wood  screws.    These  furrings  were,  of  course, 
not  exposed  to  view,  but  they  nevertheless  placed  the  cars  outside  of 
the  classification  "all  steel  cars."  The  idea  that  it  was  necessary  to  use 
wood  furrings  in  order  to  make  it  possible  to  apply  steel  finish,  or  in 
other  words,  that  wood  screws  had  to  be  used,  machine  screws  not 
being  considered  practicable,  accounts  to  some  extent  for  the  tardiness 
in  the  introduction  of  steel  in  the  interior  finish. 

4  The  earlier  specifications  and  designs  for  steel  passenger  cars 
made  the  use  of  machine  screws  for  applying  the  interior  finish  prohib- 
itive and  impossible,  which,  of  course,  made  it  necessary  to  employ  other 
means  such  as  bolts  or  wood  screws.   Bolts  for  this  purpose  must  have 
heads  of  special  design  to  allow  their  insertion  through  slotted  holes, 
etc.,  and  to  prevent  them  from  falling  through  during  the  application 
of  the  nuts.     The  nuts,  being  exposed,  are  objectionable  as  they  give 

Assistant  Mechanical  Engineer,  Pressed  Steel  Car  Company. 

Presented  at  the  New  York  Meeting,  April  1913,  of  THE  AMERICAN  So^ 
CIETY  OF  MECHANICAL  ENGINEERS. 

45 


46  STEEL  INTERIOR  FINISH  FOR  STEEL  PASSENGER  CARS 

an  unsightly  appearance,  even  if  special  cap  nuts  are  used  in  place  of 
the  ordinary  nuts,  besides  there  are  many  places  on  a  car  at  which  it 
is  impracticable  to  apply  bolts.  Therefore,  to  avoid  machine  screws 
and  bolts  the  space  between  the  outside  sheets  and  the  interior  finish 
was  filled  with  wood  furring  to  allow  for  the  use  of  wood  screws. 
The  objections  to  machine  screws,  caused  by  the  belief  that  they  would 
work  loose  in  a  short  time,  has,  however,  disappeared,  from  experience 
gained  through  actual  service  as  it  has  been  shown  that  if  set  in  white 
lead  and  properly  applied  they  are  entirely  reliable. 

5     There  has  always  been  and  there  still  is  a  great  difference  of 
opinion  as  to  how  far  it  is  advisable  to  substitute  metal  for  wood  in 
passenger  car  construction.     The  use  of  a  small  amount  of  wood  in 
the  interior  finish,  as  for  instance  window  sash  moldings,  seat  arm 
rests,  window  capping,  etc.,   should  not  be  objectionable  as  it  has 
certain  advantages  over  steel  which  are  desirable,  but  wood  is  used 
for  such  dietails  to  a  considerable  extent,  and  hundreds  of  cars  are 
now  in  service  in  which  the  small  amount  of  wood  used  in  the  interior 
finish  cannot  be  detected  except  by  an  expert  and  such  cars  are  to  all 
intents  and  purposes  fireproof  cars,  but  the  aim  of  many  designers 
has  been  to  eliminate  the  wood  wherever  possible  on  account  of  the 
many  advantages  possessed  by  steel,  among  which  may  be  mentioned : 
a     Steel  finish  means  non-combustion  in  case  of  fire. 
b     Steel  prevents  splintering  in  case  of  wreck. 
c    .Steel  finish  can  be  easily  removed  should  it  become  neces- 
sary to  repaint  the  car  at  the  inside  surface  of  steel  sheets, 
as  the  life  of  the  steel  car,  to  a  certain  extent,  depends 
on  the  condition  of  the  paint. 

d  Steel  finish  makes  it  possible  to  increase  the  interior  width 
of  the  car  where  outside  width  is  limited.  This  has  been 
found  particularly  valuable  in  designing  subway,  elevated 
or  suburban  steel  passenger  equipment  cars. 
e  Steel  finish  will  avoid  trouble  which  may  be  experienced 
due  to  different  expansion  of  materials,  steel  against 
wood.  This  point  need  not  be  considered  with  steel  and 
makes  it  unnecessary  to  provide  for  relief  in  all  members  of 
the  finish  running  longitudinally,  such  as  upper  and  lower 
deck  sill  moldings,  etc.  In  fact,  the  steel  finish  has 
revolutionized  to  some  degree  the  designs  of  wood  finish 
in  the  wooden  cars  built  since  steel  cars  came  in  vogue. 
The  cars  of  today  are  built  on  more  sanitary  lines,  and 


FELIX  KOCH  47 

fancy  moldings,  fretwork  and  carvings  have  disappeared 
without  losing  sight  of  giving  the  cars  an  artistic  finish, 
avoiding  thereby  lodging  and  breeding  places  for  all  kinds 
of  germs  which  the  world  is  fighting  against  today. 

Steel  finish  will,  by  comparison,  be  cheaper  every  year 
for  the  reason  that  it  becomes  more  difficult  to  obtain  the 
right  kind  of  lumber  for  interior  finish,  which,  of  course, 
means  increase  in  price  of  wooden  cars. 

It  is  continuously  becoming  more  difficult  to  obtain  men 
who  have  had  sufficient  experience  in  applying  wood  inter- 
ior finish,  whereas  it  does  not  take  the  same  experienced 
men  for  applying  steel  finish.  A  man  requires  from 
three  to  four  years'  apprenticeship  to  become  an  expert 
able  to  apply  wood  finish  to  a  car,  whereas  an  average 
intelligent  man  who  is  familiar  with  tools  is  able  to 
become  an  expert  in  finishing  cars  with  steel  finish  in  from 
six  to  twelve  months,  and  this  fact  of  labor  will  have  to  be 
taken  into  account  sooner  or  later. 

A  more  uniform  color  can  be  maintained  on  steel  finish 
than  on  wood  which  comes  in  different  shades,  and  it  is 
very  difficult  and  expensive  to  match  perfectly  all  parts  in 
one  car  with  regard  to  shade  without  additional  expense 
of  glazing.  Furthermore,  the  average  life  of  paint  applied 
to  steel  finish  will  be  much  greater  than  to  wood  finish  for 
the  reason  that  wood  darkens  with  age.  This,  of  course, 
influences  the  paint  which  is  a  disadvantage  from  the 
standpoint  of  illumination.  Should  it  become  necessary 
to  repaint  a  car  of  wood  finish,  reworking  of  the  finish  by 
removal  of  the  varnish  and  scraping  is  necessary,  whereas 
in  the  steel  finish  the  scraping  is  eliminated  and  the 
removing  of  varnish  is  alone  required  to  be  able  to  repaint 
the  car. 

Steel  finish  is  of  advantage  from  a  building  standpoint  in 
the  handling  and  working  up  of  material  to  make  ready  for 
application.  Steel  details  can  be  worked  up  to  a  large 
extent  before  they  are  applied  to  the  cars,  which  make  it 
possible  to  manufacture  the  interior  finish  in  much  less 
time  by  the  use  of  more  men  than  it  is  possible  to  employ 
when  applying  a  wood  finish,  as  only  a  limited  number  of 
men  have  room  to  work  at  the  same  time  in  a  car  when  the 
greater  part  of  the  fitting  and  cutting,  etc.,  has  to  be  done. 


48  STEEL  INTERIOR  FINISH  FOR  STEEL  PASSENGER  CARS 

This  has  facilitated  the  •  establishment  of  a  number  of 
manufacturing  concerns  who  devote  their  efforts  almost 
exclusively  to  producing  steel  interior  finishes  not  only 
for  passenger  cars  but  also  for  buildings.  In  addition  to 
these  any  manufacturing  company  equipped  with  the 
necessary  machinery  for  the  making  of  drawn  moldings, 
breaker  presses,  and  ordinary  welding  and  spot  welding 
machines,  is  able  to  handle  this  class  of  work  for  railroads 
or  carbuilders,  who  may  not  have  the  necessary  equipment 
to  do  the  work  in  their  own  shops  and  prefer  to  buy  the 
interior  finish  as  they  buy  other  specialties. 

6  All  of  these  advantages  are  almost  exclusively  confined  to  the 
use  of  steel  or  other  metals,  although  a  composite  material  of  a  wood 
pulp  nature  or  similar  material  made  fireproof  and  waterproof  by 
different  processes,  if  applied  in  a  proper  way  and  used  for  ceilings 
and  below  the  window  sills,  is  not  objectionable,  and  it  may  be  ap- 
plied in  practically  the  same  manner  as  steel. 

7  The  advantages  possessed  by  wood  over  metal  as  a  non-conduc- 
tor can  be  very  much  reduced  by  the  use  of  proper  insulating  material 
correctly  applied.    The  use  of  proper  insulation  is  of  course  of  great 
importance  and  manufacturers  of  that  class  of  material  as  well  as 
railroads  and  car  builders  are  giving  a  great  deal  of  attention  to  the 
subject,  and  the  time  does  not  seem  to  be  far  distant  when  steel  cars 
with  interior  finish  of  wood  will  be  as  scarce  as  steel  passenger  cars 
were  ten  years  ago. 

8  A  great  deal  more  could  be  said  on  this  subject,  but  it  is  hoped 
that  what  has  been  brought  out  will  show  that  steel  interior  finish 
has  certain  advantages  not  possessed  by  other  material  commonly  used 
in  passenger  cars  and    that    the    disadvantages    are    few    and    not 
insurmountable. 


No.  1388  h 

PAINTING  OF  STEEL  PASSENGER  CARS 

BY  C.  D.  YOUNG,  ALTOONA,  PA. 
Member  of  the  Society 

A  fundamental  reason  for  painting  any  surface  of  a  passenger 
car  is  to  protect  it  from  the  damaging  effects  of  the  air  which  is  more 
or  less  loaded  with  gases  and  moisture.  For  example,-  oxygen  is 
destructive  of  iron  and  steel  and  when  sulphurous  gases  are  present 
they  are  quickly  oxidized  into  sulphuric  acid  which  is  very  corrosive 
to  unprotected  metallic  surfaces.  It,  therefore,  becomes  necessary  to 
protect  the  surface  by  a  covering,  and  paint  forms  a  substantial  and 
convenient  means  for  accomplishing  this.  If  properly  made  and 
applied,  it  is  an  impervious  coating,  affording  the  needed  protection 
by  forming  a  hard  waterproof,  rubber-like  sheeting  or  film  which  has 
sufficient  elasticity  to  conform  itself  to  the  contraction  and  expansion 
of  the  surfaces  to  which  it  is  applied.  In  addition  to  protection  the 
surfaces  may  be  beautified  and  embellished  by  the  proper  selection  of 
pigments  so  as  to  bring  about  the  harmonizing  and  artistic  effects 
desired. 

WOODEN   EQUIPMENT 

2  The  painting  of  wooden  passenger-car  equipment  has  been,  in 
the  main,  successfully  accomplished,  the  painting  schedule  for  the 
outside  is  briefly  as  follows:    Apply  two  coats  of  primer,  putty  and 
glaze,  followed  by  three  or  four  coats  of  surfacers,  as  found  necessary, 
after  which  the  surfaces  are  rubbed  down  smooth  with  emery  and  oil, 
when  two  coats  of  shade  color  are  put  on.     The  necessary  striping 
and  lettering  follows,  completing  by  three  coats  of  finishing  varnish, 
consuming  in  all  about  sixteen  to  eighteen  days. 

3  The  finishing  of  the  interior  of  wooden  cars  generally  has  been 
in  the  natural  wood,  consequently  it  is  only  necessary  to  prepare  the 
surface  for  the  varnishing.     A  representative  schedule  which  is  used 
is  as  follows:  One  coat  of  filler,  in  paste  form,  which  is  sandpapered 
down  to  a  smooth  finish.    Add  one  coat  of  rubbing  varnish  and  rub 
down  with  sandpaper,  after  which  apply  three  coats  of  rubbing  varnish, 

Presented  at  the  New  York  Meeting,  April  1913,  of  THE  AMERICAN  SO- 
CIETY OF  MECHANICAL  ENGINEERS. 

49 


50  PAINTING  OF  STEEL  PASSENGER  CARS 

and  complete  the  finish,  cutting  down  the  gloss  by  rubbing  with  pumice 
and  oil  to  produce  the  most  pleasing  "flat  finish." 

4  This  method  of  finishing  the  wooden  surfaces  of  cars  has  been 
attained  with  good  results,  so  that  naturally  when  the  change  to  steel 
passenger  equipment  came  some  six  years  ago,  a  desire  to  retain  as 
much  past  practice  as  possible  seemed  desirable.     It  was  realized, 
however,  that  the  all  important  point  in  the  painting  of  iron  or  steel 
surfaces  was  to  have  the  surfaces  first  thoroughly  cleaned  and  entirely 
rid  of  scale  and  rust,  as  this  is  as  necessary  as  the  painting  itself. 
To  accomplish  this,  sand-blasting,  where  possible,  was  resorted  to, 
supplemented  by  the  use  of  wire  brushes  and  emery  cloth  in  the  more 
obscure  places  and  the  more  uneven  surfaces.    The  sand-blasting,  how- 
ever, was  confined  largely  to  the  outside  surfaces  and  the  latter  prac- 
tices to  the  inside  portion  of  the  car. 

5  Iron  and  steel,  while  not  presenting  to  the  eye  the  same  porous 
condition  as  wood,   is  full   of  finely   divided  pores,   and  the   same 
atmospheric  influences  which  enter  the  pores  of  wood  and  cause  it  to 
d,ecay  are  ever  ready  to  attack  the  unpainted  surfaces  of  iron  and  steel, 
in  fact  the  metal  surfaces  more  readily  combine  with  the  oxygen  and 
moisture  of  the  air,  forming  what  is  rust  or  oxide  of  iron.    Therefore, 
immediately  after  the  sand-blasting  and  cleaning  of  the  surfaces  should 
come  the  application  of  the  first  or  primary  coat,  as  this  is  the  most 
important  one,  from  the  preservative  standpoint. 

6  In  the  selection  of  a  suitable  primer  it  seemed  but  natural  for 
the  painter  to  be  guided  by  the  experience  gained  in  the  painting  of 
locomotive  tenders,  and  to  follow  the  initial  coats  with  practically  the 
same  process  as  with  wooden  cars,  and  I  believe  that  so  far  as  the 
subsequent  coats  are  concerned,  this  practice  was  generally  carried  out 
by  the  earlier  painting  of  steel  passenger  equipment.     It  is  thought 
that  an  error  has  been  made  in  this  general  practice,  as  will  be 
explained  later. 

STEEL   EQUIPMENT 

7  The  schedule  for  painting  steel  passenger  car  trucks,  under- 
frames  and  superstructures  is  as  follows: 

8  Trucks.      Before    assembling,    all    surfaces    on    truck    parts 
throughout,  including  all  concealed  surfaces,  but  not  including  wheels 
and  axles,  must  be  covered  with  one  coat  of  suitable  primer.     After 
assembling,  all  surfaces'  (except  wheels)   exposed  to  view  after  the 
body  of  the  car  has  been  placed  on  trucks,  must  be  covered  with  two 
coats  of  truck  enamel. 


C.  D.  YOUNG  51 

9  Under  frames.     During  the  process  of  construction,  all  parts 
of  the  underframe,  including  concealed  surfaces  and  surfaces  where 
metal  bears  on  metal,  must  be  covered  with  two  coats  of  good  metal 
preservative  of  a  non-inflammable  nature.     All   accessible  surfaces 
must  be  covered  with  a  third  coat  of  metal  preservative. 

10  Superstructures.     Before  assembling,  all  parts  made  of  iron 
or  steel,  including  the  roof,  must  be  covered  with  one  coat  of  primer. 
A  second  coat  of  primer  properly  thinned  with  turpentine,  or  similar 
material,  must  be  applied  to  all  surfaces,  including  those  which  are 
concealed  when  the  car  is  completed.    Wherever  possible,  this  second 
coat  must  be  put  on  after  the  sheets  are  in  place. 

11  After  assembling,  the  outside  of  side  and  end  sheeting,  in- 
cluding letter  plate  and  deck  plate,  must  be  covered  with  one  coat  of 
surfacer,  the  rough  and  uneven  places  glazed  with  "surfacer  composi- 
tion," four  coats  of  surfacer  being  added,  rubbed  down  with  linseed 
oil  and  emery  cloth,  two  coats  of  desired  color  material  added,  followed 
by  striping  and  lettering,  then  finished  with  three  coats  of  finishing 
varnish.     The  outside  of  the  roof  must  be  finished  with  one  coat  of 
heavy  protective  paint,  followed  by  one  coat  of  a  mixture  composed 
by  volume  of  three  parts  of  mixed  ground  color  and  one  part  of  the 
protective  coating  used.     The  top  surface  and  edges  of  headlining 
should  be  painted  with  two  coats  of  some  preservative,  or  color  paint. 

12  The  interior  of  cars  should  receive  very  careful  attention  in 
order  to  produce  the  desired  finish.     To  illustrate  fully  the  various 
steps  and  time  taken  to  complete  the  painting,  the  following  is  given 
as  outlining  the  progress  of  the  work.    This  is  attained  with  the  use 
of  surfacers,  colors  and  varnishes  containing  a  relatively  large  amount 
of  artificial  driers  and  varnish  gums,  in  order  to  obtain  the  artistic 
finish  desired  for  the  interior. 

HEADLINING 

1st  day  Apply  one  coat  and  stipple  after  application. 

2d   day  Stand  for  drying. 

3d   day  Apply  one  coat  and  stipple  after  application. 

•   4th  day  Stand  for  drying. 

5th  day  Apply  one  coat  and  stipple  after  application. 

SIDES  ABOVE  WINDOW  SILLS  AND  ENDS 

1st  day  Apply  one  coat  or  priming. 

2d   day  Stand  for  drying. 

3d   day  Apply  one  coat  surfacer. 

4th  day  Necessary  puttying  and  glazing. 


52 


PAINTING  OF  STEEL  PASSENGER  CARS 


5th  day  Apply  as  many  coats  surf  acer  as  are  necessary  to  make  a  level 
surface. 

6th  day  Same  as  5th  day. 

7th  day  Eub  down  with  emery  and  linseed  oil. 

8th  day  Apply  one  coat  of  ground  color. 

9th  day  Apply  one  coat  of  ground  color. 

10th  day  Apply  one  coat  of  ground  color, 

llth  day  Apply  one  coat  and  stipple  after  application. 

12th  day  Apply  one  coat  rubbing  varnish. 

13th  day  Stand  for  drying. 

14th  day  Apply  one  coat  rubbing  varnish. 

15th  day  Stand  for  drying. 

16th  day  Apply  one  coat  rubbing  varnish. 

17th  day  Stand  for  drying. 

18th  day  Eub  with  oil  and  pulverized  pumice  stone. 

SIDES    BELOW    WINDOWS 

1st  day  Apply  one  coat  or  priming. 

2d   day  Stand  for  drying. 

3d   day  Apply  one  coat  surf  acer. 

4th  day  Necessary  puttying  and  glazing. 

5th  day  Same  as  6th  day. 

6th  day  Apply  as  many  coats  surfacer  as  are  necessary  to  make  a  level 
surface. 

7th  day  Eub  down  with  emery  and  linseed  oil. 

8th  day  Stand,  awaiting  bringing  up  other  work. 

9th  day  Stand,  awaiting  bringing  up  other  work. 

10th  day  Apply  one  coat  bronze  green. 

llth  day  Apply  one  coat  bronze  green. 

12th  day  Apply  one  coat  of  rubbing  varnish. 

13th  day  Stand  for  drying. 

14th  day  Apply  one  coat  of  rubbing  varnish. 

15th  day  Stand  for  drying. 

16th  day  Apply  one  coat  of  rubbing  varnish. 

17th  day  Stand  for  drying. 

18th  day  Eub  with  oil  and  pulverized  pumice  stone. 

13  Formulae  and  panels  for  the  various  shade  should  be  furnished 
the  painters  for  their  guidance  in  obtaining  the  shade  of  any  of  the 
colors  which  are  desired. 


RESULTS  OF  AIR  DRYING  PAINTS  ON  STEEL 

14  The  artificial  driers  and  gums  used  in  hastening  the  time  of 
drying  and  hardening  of  the  various  coats  and  permitting  the  neces- 
sary rubbing  continue  this  action  so  that  the  paints  and  varnish 
increase  in  hardness  and  brittleness,  rendering  them  susceptible  to 


C.  D.  YOUNG  53 

cracking  and  chipping,  and  the  process  of  disintegration  is  aggravated 
by  excessive  expansion  and  contraction  of  the  steel  surfaces  as  com- 
pared with  wood.  The  linear  expansion  of  steel  being  more  than  twice 
that  of  wood  would  seem  to  indicate  the  use  of  more  elastic  coatings 
than  formerly  used  for  wooden  cars. 

15  This  fact  has  been  borne  out  in  the  service  of  the  paint  in  a 
great  many  cases  in  an  investigation  which  recently  came  under  my 
observation.     It  was  noticed  that  when  some  of  the  equipment  had 
been  in  service  about  four  months,  the  interiors  of  the  cars  were 
showing  varnish  cracks  and  checks.    As  time  went  on  more  cars  gave 
evidence  of  this  deterioration,  the  final  outcome  being  that  an  investi- 
gation was  made  to  see  how  serious  the  condition  was.    Some  400  cars 
were  carefully  examined,  special  attention  being  given  to  the  selection 
of  cars  built  by  various  manufacturers,  where  different  makes  of  sur- 
facers  and  varnishes  were  employed.     An  endeavor  was  also  made  to 
determine  whether  the  cracking  of  the  painted  surfaces  was  confined 
to  the  varnish  coats  or  the  surfacer  coats,  or  both. 

16  In  order  to  classify  the  various  conditions  found,  four  readings 
of  percentages  were  arbitrarily  taken,  the  condition  of  a  new  car  being 
taken  at  100  per  cent: 

Per  cent  Condition  of  Varnish  and  Surface 

90  to  80 Good,   no   checking 

80  to  70 Fair,  slight  checking 

70  to  60 Medium,  considerable  checking 

60  to  50 Poor,  checked  from  outside  varnish  coat  to  metal 

Sample  cars  were  selected  to  illustrate  these  various  classes,  and 
photographs  were  taken  of  the  different  defective  surfaces  so  as  clearly 
to  indicate  to  the  eye  what  the  different  percentages  meant. 

17  The  result  of  this  examination  showed  that  the  exteriors, 
including  the  sides,  ends  and  vestibules,  were  in  fair  condition.    There 
were  a  few  exceptions  to  this,  but  they  amounted  to  less  than  6  per 
cent  of  the  total  having  serious  varnish  and  surface  cracks.     Inter- 
iors were  found  generally  to  be  in  a  poor  condition.    About  80  per  cent 
of  the  equipment  examined  had  the  varnish  checked  through  to  the 
surfacer. 

18  Some  of  these  conditions  developed  after  four  to  eight  months' 
service,  indicating  either  that  an  entirely  new  system  of  painting 
would  be  necessary  to  overcome  these  troubles,  or  that  a  more  elastic 
paint  would  have  to  be  used  for  interior  finishing  under  the  present 
existing  practice  of  painting  steel. 


54  PAINTING  OF  STEEL  PASSENGER  CABS 

19  To  obtain  some  data  indicating  what  should  be  done  to  meet 
the  conditions,  preliminary  experiments  were  made  by  painting  a 
number  of  panels  and  baking  them  in  a  heated  oven.  Eepeated  experi- 
ments along  this  line  indicated  that  artificial  driers  could  almost,  if 
not  entirely,  be  eliminated  in  the  paint  formulae  and  that  more  elastic 
materials  could  be  used  without  the  aid  of  artificial  oxidizing  agents. 
It  was  also  observed  that  the  elastic  varnish  used  on  the  exterior 
of  the  cars  could,  under  this  system,  be  used  to  advantage  on  the 
interior,  and  by  the  aid.  of  the  heat  of  the  oven  they  could  be  dried 
to  the  desired  hardness,  permitting  the  rubbing  with  oil  and  pumice  to 
get  the  "flat  finish." 

20  The  outcome  of  the  experiments  indicated  that  it  would  be 
desirable  to  extend  the  experimental  panels  to  a  full  size  car  and, 
therefore,  a  proper  baking  oven  was  planned  that  would  accommodate 
one  of  the  largest  existing  steel  passenger  cars  for  the  purpose  of 
baking  each  coat  as  applied  to  the  exterior  and  interior  surfaces. 

i21  This  oven,  as  designed  and  built  by  the  Pennsylvania  Eailroad 
Company  at  its  Altoona  shops,  is  90  ft.  3  in.  long,  13  ft.  wide  and  15 
ft.  high.  The  frame  work  of  this  structure  is  made  up  of  3-in.  I-beams 
for  the  sides,  spaced  5  ft.  centers.  The  roof  framing  is  made  of  the 
same  sections  and  curved  to  conform  closely  to  the  contour  of  the  car 
roof.  Each  end  of  the  oven  has  two  large  doors  which  can  be  readily 
opened  and  closed  for  the  baking  operation.  The  oven  is  lined  on  the 
inside  with  %-in.  steel  plate,  and  on  the  outside  with  galvanized  iron 
of  0.022  gage.  The  3-in.  space  is  filled  with  magnesia  lagging,  thus 
effecting  the  needed  insulation.  The  doors  are  insulated  in  a  similar 
manner.  Along  the  walls  of  the  interior  of  the  oven  are  placed  16 
rows  of  1%-in.  steam  pipes,  and  along  the  floor,  close  to  the  walls,  are 
arranged  manifold  castings  with  small  lengths  of  pipe  tapped  into 
them  at  right  angles.  By  this  means  over  2000  sq.  ft.  of  heating 
surface  is  provided.  A  steam  pressure  of  approximately  100  Ib.  to 
the  square  inch  is  used,  thus  making  it  possible  to  get  an  oven  tempera- 
ture of  over  250  deg.  fahr.  Eectangular  openings,  made  adjustable, 
are  provided  on  the  sides  near  the  floor  line,  allowing  the  necessary 
admission  of  air  for  circulation.  Four  8-in.  Globe  ventilators  are 
spaced  at  equal  distances- in  the  roof,  likewise  provided  with  dampers 
to  regulate  the  size  of  the  opening.  By  this  means  of  ventilation, 
fresh  air,  which  is  required  for  the  proper  drying  of  paint,  is  obtained, 
as  well  as  providing  for  the  egress  of  the  volatile  matter  present. 
Automatic  ventilation  and  steam  regulation  have  not,  at  the  present 


C.  D.  YOUNG 


55 


time,  been  applied,  but  these  have  been  considered  advisable,  if  the 
result  of  the  experiment  seems  to  warrant  a  more  extended  application 
of  the  practice. 

22  A  track  is  placed  on  the  floctr  of  the  oven  and  connected  at 
each  end  of  the  oven  with  other  tracks  leading  into  the  regular  paint 
shop  where  the  different  coats  of  paint  are  aplied  to  the  car  before 
each  baking  operation. 


FIG.  1     EXTERIOR  APPEARANCE  OF  OVEN 

23  Photographs  of  the  general  appearance  of  this  oven  from  the 
outside,  and  one  end  of  the  interior  with  a  car  within  the  oven  are 
shown  in  Figs.  1  and  2.  Fig.  3  shows  the  steam  piping  in  detail. 


BAKING  PAINT   ON   STEEL 

24  The  outline  of  painting  a  car  in  this  oven  is  briefly  as  follows : 
First,  a  priming  coat  is  given  the  exterior  and  interior  of  car,  which 
is  then  moved  into  the  oven  and  baked  for  three  hours.  •  The  tem- 
perature at  the  start  is  about  160  deg.,  but  rapidly  rises  at  about  1 
deg.  per  min.  until  a  temperature  of  250  deg.  is  reached,  requiring 
about  iy2  to  2  hours.  The  oven  is  held  at  this  temperature  until  the 
lapse  of  3  hours,  when  the  car  is  withdrawn,  allowed  to  cool  sufficiently 
to  work  upon,  after  which  the  surfaces  are  glazed  and  depressions  and 


56 


PAINTING  OF  STEEL  PASSENGER  CARS 


uneven  places  puttied.  The  car  then  receives  its  first  coat  of  surfacer, 
is  returned  to  the  oven  for  3  hours,  baked  and  removed  for  additional 
coats  which  vary  from  two  to  three  in  number  as  the  needs  of  the  case 
require. 

25     After  the  last  coat  of  surfacer  has  been  applied  and  baked, 
the  outside  surface  of  the  body  of  the  car  is  rubbed  down  with  emery 


FIG.  2    VIEW  OF  INTERIOR  OF  OVEN  SHOWING  CAR  IN  PLACE 


and  oil  to  produce  a  flat  and  smooth  surface.  The  various  color 
coats  used,  such  as  tuscan  red  on  the  outside,  pale  green,  bronze,  and 
bronze  green  on  the  inside,  are  then  put  on.  Two  coats  of  each  color 
are  required  to  get  standard  shades.  Each  coat  of  color  is  likewise 
baked. 


C.  D.  YOUNG 


57 


'1 

IE 

tJJ 

C 

== 

0 

s 

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1|, 

=*<JS- 
^U-'' 

i 

If 
II 

^ 

58 


PAINTING  OF  STEEL  PASSENGER  CARS 


TABLE  1      TIME  SCHEDULE  FOR  PAINTING  EXTERIOR  AND  INTERIOR  OF 
STEEL  PASSENGER  CARS 


OUTSIDE 

INSIDE 

Period 
of 
Work 

Body 

Roof 

Trucks 

Body  Above 
Window  Sills 

Headlining 

Body  Below 
Window  Sills 

1 
2 
3 

4 

1st  prime 
glaze 
1st  surface 
2d  surface 

1st  prime 
2d  prime 

.... 

1st  prime 
glaze 
rub-ground 

1st  prime 
glaze 
rub 

1st  prime 
glaze 
rub 

5 

3d  surface 

6 

rub 

7 
8 
g 

1st  tuscan 
2d  tuscan 
stripe  and  letter 

3d  prime 

2d  ground 
stipple 

1st  green 

1st  green 

10 
11 
12 
13 

1st  varnish 
2d  varnish 
3d  varnish 

.... 

truck 
color 

1st  varnish 
2d  varnish 
3d  varnish 
rub 

2d  green  air 

2d  green 
1st  varnish 

t 

dry 

2-6  The  car  then  receives  the  required  lettering,  striping,  etc., 
after  which  the  outside  and  inside  surfaces  get  three  coats  of  a  high 
grade  finishing  varnish,  especially  adapted  for  the  baking  process. 
Each  coat  of  varnish  is  baked  at  .a  temperature  from  120  deg.  fahr. 
at  the  start  to  150  deg.  fahr.,  which  is  maintained  until  the  expiration 
of  3  hours.  The  interior  surfaces  of  the  car  are  then  rubbed  with 
pumice  and  oil,  giving  the  "flat  finish"  effect  desired,  thus  completing 
the  painting  of  the  car. 

27  To  illustrate  better  the  schedule  of  operation  followed,  or  the 
timing  of  the  various  coats,  both  for  the  outside  and  inside,  to  secure 
the  most  economical  conditions,  Table  1  is  given. 

2&  All  of  the  work  done  by  the  baking  process  of  painting  can  be 
accomplished  in  six  to  eight  days,  thus  effecting  a  saving  in  time  of 
about  ten  days  as  compared  with  the  standard  or  present  air  drying 
system.  Further,  the  paints  and  varnishes  have  been  worked  up  so 
that  they  are  especially  adapted  for  this  baking  process,  having  greater 
elasticity.  Exact  formulae  for  the  various  mixtures  are  well  defined, 
so  that  uniformity  in  material  is  expected,  thus  giving  greater  dura- 
bility, better  appearance  and  longer  life  for  the  paint  work. 

29  The  checks  and  cracking  previously  found  will  be  considerably 
lessened,  if  not  almost  removed.  By  oven  painting  the  work  is  done 


C.  D.  YOUNG  59 

under  more  uniform  conditions,  which  at  the  present  time  are  so  hard 
to  control.  It  enables  the  surfaces  of  the  car  to  be  heated  uniformly 
and  dried  thoroughly,  thus  removing  any  objectionable  moisture  before 
the  first  priming  coat  is  applied,  which  is  a  very  desirable  feature  of 
the  new  method. 

30  A  considerable  saving  will  be  effected  by  the  shorter  time  that 
cars  will  be  held  out  of  service  when  undergoing  repairs  and  repainting 
in  the  shops.  It  is  expected  that  dirt,  soot,  etc.,  will  not  adhere  or 
imbed  themselves  so  readily  and  that  the  general  appearance  of  the  car 
will  be  improved  by  the  baking  method. 

3il  This  oven  was  placed  in  service  the  early  part  of  this  year  and 
the  results  of  the  complete  car  at  this  time  seem  to  justify  the  experi- 
ment. They  seem  to  indicate  that  the  results  obtained  from  a  small 
panel  can  be  duplicated  in  the  full  size  passenger  equipment  car 
and  that,  if  this  is  the  case,  this  method  of  painting  can  be  used  to 
advantage  not  only  for  the  painting  of  steel  passenger  equipment  cars, 
but  for  the  painting  of  any  other  full  size  steel  structure  of  a  similar 
character  where  protection  and  finish  are  desired. 

32  Eesults  and  indications  at  this  time  seem  to  justify  our 
expectations  that  the  new  process  of  baking  will  give,  over  the  present 
air  drying  system:  (a)  Longer  life  of  material  applied;  (&)  a  general 
appearance  as  good  or  better;  (c)  less  cost  of  material  at  no  increase 
in  the  labor  charge;  (d)  complete  sanitation  for  old  cars;  (e)  a  con- 
siderable saving  of  time  for  shopping  cars,  which  results  in  a  saving 
of  shop  space.  These  advantages  are  offset  by  the  initial  cost  of 
installation  and  operating  cost  of  the  oven. 


1388  i 

PROVISIONS  FOR  ELECTRIC  LIGHTING  IN 
STEEL  PASSENGER  CARS 

BY  H.  A.  CURRIED  NEW  YORK 
Non-Member 

Hardly  more  than  perfunctory  attention  is,  as  a  rule,  given  to 
the  lighting  equipment  of  a  car  by  the  car  designer.  After  all  other 
apparatus  and  equipment  are  taken  care  of,  the  lighting  is  considered 
and  fitted  as  well  as  possible  into  the  remaining  space. 

2  From  a  standpoint  of  practical  consideration  of  the  welfare  of 
passengers,  the  lighting  plays  one  of  the  most  important  parts ;  there- 
fore, every  effort  should  be  made  to  arrange  the  light  units  so  that  no 
discomfort  be  occasioned,  and  to  install  the  apparatus  and  wiring  so 
that  operating  failures  be  reduced  to  a  minimum.    In  this  connection 
I  might  say  that  the  United  States  postal  authorities  at  Washington 
are  going  into  this  subject  very  carefully  at  the  present  time  to  insure 
fair  treatment  for  their  postal  clerks  in  the  railway  mail  service ;  very 
stringent  requirements  have  been  ordered  both  as  regards  general 
illumination  and  reliable  performance. 

3  ,The  two  essential  considerations  for  the  designing  engineer  to 
keep  in  mind  in  laying  out  his  installation  are :  (a)  The  arrangement 
of  parts  in  a  manner  to  allow  of  easy  inspection  and  repair;  (6)  pro- 
tection against  mechanical  injury.     Convenience  and  accessibility  of 
apparatus,  fixtures,  junction  boxes  and  wiring  mean  much  to  the 
inspector.    It  is  a  well-known  fact  that  the  average  inspector  will  pay 
little  attention  to  those  parts  which  are  difficult  of  access,  and  much 
better  inspection  work  will  result  where  parts  are  arranged  in  an 
accessible  manner.     It  is  of  equal  importance  that  the  various  parts 
be  protected  in  such  a  manner  as  to  avoid  all  possibility  of  injury  to 
them  while  the  car  is  in  service.    The  other  essential  features  of  the 
lighting  installation  are  discussed  in  the  following  paragraphs: 

4  Axle  Generator.    The  usual  practice  is  to  suspend  the  generator 
by  swinging  links  at  the  inside  end  of  the  truck,  and  belt  it  to  a  pulley 

Assistant  Electrical  Engineer,  N.  Y.  C.  &  H.  K.  E.  R. 

Presented  at  the  New  York  Meeting,  April  1913,  of  THE  AMERICAN  SO- 
CIETY OF  MECHANICAL  ENGINEERS. 

60 


H.  A.  CURRIE  61 

on  the  axle.  For  mounting  the  axle  pulley  a  straight  machined  seat 
should  be  provided  in  all  cases  if  electric  lighting  is  planned  or  can  be 
anticipated.  Until  recent  years  the  universal  practice  was  to  provide 
the  regulation  tapered  axle  and  allow  the  manufacturer  of  electric 
lighting  equipments  to  adapt  his  pulley  to  an  unsuitable  seat  in  the 
best  manner  he  could.  The  belt  and  pulley  troubles  which  resulted 
were  disproportionate  to  any  possible  advantage  from  retaining  the 
tapered  axles.  It  is  customary  for  the  manufacturer  of  lighting 
equipments  to  provide  his  own  supporting  structure  adapted  as  cir- 
cumstances permit  for  attachment  to  the  truck.  The  resulting  suspen- 
sion is  at  best  something  of  a  makeshift. 

5  It  would  be   a  consummation  much  to  be   desired  if  truck 
designers  would  provide  a  generator  support  built  integral  with  the 
truck;  the  requirements  are  not  difficult  and  it  is  certain  that  the 
generator  builders  would  be  glad  to  make  their  machines  conform  to 
the  truck  builder's  suspension.    As  the  matter  is  now  handled,  nothing 
causes  them  more  delay  and  inconvenience  than  obtaining  the  numer^ 
ous    details   of   truck   and   underframe   construction   necessary   for 
making  an  intelligent  layout  of  the  generator  suspension.    In  design- 
ing the  suspension  it  is  desirable  that  the  space  required  for  the  belt 
be  kept  as  clear  as  possible.     The  end  tie  of  the  truck  frame,  if  used, 
should  not  be  deep  and  should  be  located  at  a  level  that  will  make  it 
possible  for  the  belt  to  straddle  it.     Outside  brake  beams  when  used 
are  a  necessary  evil  from  the  standpoint  of  generator  location.    Head 
room  for  the  generator  should  be  considered  in  laying  out  deep  center 
girders,  brake  rigging  and  piping.     All  the  open  space  that  can  be 
provided  about  the  generator  is  desirable  because  it  facilitates  thorough 
inspection.     The  generator  terminal  board  should  be  attached  to  the 
underframe  of  the  car  close  to  the  generator  and  readily  accessible. 

6  Battery  Box.    On  account  of  the  obvious  necessity  for  conven- 
ience in  handling  the  heavy  batteries,  the  battery  box  location  has 
practically   been   standardized.     As   the   weight   and   dimensions   of 
elements  are  almost  identical,  it  is  unnecessary  to  change  the  hanger 
design  after  a  satisfactory  arrangement  has  once  been  used. 

7  Charging  Receptacles.      The  charging  receptacles  have  been 
allotted  a  permanent  location  on  electric  lighted  equipment.     Care 
should  be  taken  to  arrange  the  wire  leading  to  the  receptacles  to 
prevent  interference  with  brake  rods,  etc. 

8  Switchboard  and  Regulator  Lockers.       (a)    The  switchboard 
locker  should  be  so  located  as  to  be  at  all  times  easily  accessible  to  the 


62  ELECTRIC  LIGHTING  IN  STEEL  PASSENGER  CARS 

trainmen;  no  pains  should  be  spared  in  the  design  and  installation 
of  the  board;  nothing  but  fireproof  material  should  be  used.  A 
receptacle  for  spare  lamps  and  a  report  card  holder  are  convenient 
accessories,  (b)  The  regulator  locker  is  generally  located  under  the 
switchboard  and  on  the  generator  end  of  the  car.  Good  ventilation  is 
a  necessity.  Provision  against  dampness  and  dirt  is  imperative.  The 
regulator  lockers  should  be  fitted  with  locks  to  guard  against  accidental 
or  wilful  interference  with  apparatus.  In  designing  lockers  for  light- 
ing apparatus  it  is  recommended  that  liberal  space  be  provided  so 
that  changing  of  equipment,  repairing,  inspecting  and  testing  can 
be  done  to  the  best  advantage. 

9  Conduit.     In  steel-car  construction,  metal  conduits  are  almost 
universally  used.    In  the  better  type  of  steel  car  the  interior  conduits 
can  be  concealed  behind  metal  molding  and  suitable  outlet  boxes 
designed  to  harmonize  with  the  contour  of  the  molding.     Some  de- 
signers are  satisfied  to  have  exposed  conduit  used  exclusively  through- 
out the  car.    In  laying  out  wiring  conduit,  direct  runs  without  sharp 
bends  should  be  used.    Care  in  locating  the  conduits  will  facilitate  the 
installation  of  wires  and  prevent  damage  from  moisture,  etc. 

10  Fixtures.    Where  side  lighting  is  used,  a  satisfactory  arrange- 
ment can  be  obtained  by  designing  the  fixture  to  meet  the  contour  of 
the  molding.    In  center  deck  lighting,  it  is  advisable  wherever  possible 
to  arrange  the  carlines  so  that  a  direct  support  to  each  fixture  may  be 
obtained.     On  platforms  provision  for  one  or  two-lamp  outlets  is 
sufficient.    A  plain  socket  mounted  on  the  platform  ceiling  has  been 
used  in  some  instances.     A  better  arrangement  would  be  a  metallic 
reflector  sunk  flush  in  the  ceiling. 

Ill  Emergency  Lights.  It  was  formerly  customary  in  applying 
electric  light  to  retain  gas  lighting  as  a  reserve.  Increasing  reliability 
of  electric  lighting  apparatus  has  made  this  unnecessary  and  in 
the  best  present  practice  no  gas  equipment  is  provided.  For  emer- 
gencies it  is  customary  to  provide  holders  for  candle  lamps;  but  it  is 
only  on  rare  occasions  that  these  have  to  be  used,  if  the  electric 
equipment  is  of  a  good  modern  type. 


No.  1388  j 

PROVISION  FOR  ELECTRICAL  EQUIPMENT 
ON  STEEL  MOTOR  CARS 

BY  F.  W.  BUTT/  NEW  YORK 
Non-Member 

In  providing  for  the  electrical  equipment  on  steel  motor  cars, 
several  important  points  should  be  considered.  On  account  of  its 
metallic  construction,  the  car  becomes  a  negative  conductor,  or,  in 
other  words,  the  car  is  grounded,  and  all  electrical  apparatus  must 
be  well  insulated  against  leakage  of  the  electrical  current. 

2  Switches,  circuit  breakers,  fuses,  etc.,   should  be  so  located 
that  the  arc  when  opening  a  circuit  will  not  reach  the  metal  structure 
of  the  car.    In  cases  where  space  is  limited,  and  it  becomes  necessary 
to  locate  circuit  breaking  apparatus  in  such  a  way  that  there  is  danger 
of  the  arc  reaching  the  metal  structure,  suitable  arc  shields  of  non- 
conducting and  non-inflammable  material  should  be  used. 

3  iSwitches,  terminals  and  other  apparatus,  having  exposed  live 
parts,  should  be  protected  against  accidental  contact  by  enclosing 
them  in  boxes  or  cabinets.    This  protection  is  most  important  where 
apparatus,  such  as  mentioned  above,  is  located  in  or  near  the  space 
which  is  occupied  by  passengers. 

4  It  is  sometimes  found  necessary  on  account  of  the  restricted 
space  in  toilet  rooms,  motormen's  cabs,  postal  and  baggage  compart- 
ments, etc.,  to  attach  electric  heaters  directly  to  the  sheathing;  the 
heater  coils  then  are  necessarily  close  to  the  sheathing,  and  as  a 
means  of  protection  to  the  paint  and  varnish  thereon,  an  insulated 
backing  should  be  applied  between  the  sheathing  and  the  heater. 

5  Particular  attention  should  be  given  to  locking  bolts,  nuts, 
screws,  etc.,  to  prevent  them  working  loose  on  account  of  vibration, 
especially  those  which  are  used  to  secure  the  apparatus.    The  vibrations 
of  the  motor  gearing  are  transmitted  to  all  parts  of  the  car  and  they 
are  more  pronounced  when  the  motor  suspension  lug  is  mounted  on 
the  truck  transom,  without  the  use  of  suspension  springs.    Vibration 

Assistant  Engineer,  Electrical  Department,  N.  Y.  C.  &  H.  E.  E.  E. 

Presented  at  the  New  York  Meeting,  April  1913,  of  THE  AMERICAN  SO- 
CIETY OF  MECHANICAL  ENGINEERS. 

63 


64  ELECTRICAL  EQUIPMENT  ON  STEEL  MOTOR  CARS 

is  more  easily  transmitted  through  the  solid  structure  of  steel  cars 
than  it  is  in  cars  of  wood. 

6  In  the  design  of  new  cars  it  is  sometimes  found  convenient 
to  locate  various  members  of  the  structure,  especially  in  the  under- 
frame,  so  the  apparatus  can  be  suspended  from  them  without  the  use 
of  intermediate  supports.     This  is  desirable  as  it  is  often  found  that 
many  parts  can  be  omitted  from  the  car.     Where  heavy  apparatuses 
to  be  suspended  from  intermediate  supports,  large  heavy  members  are 
required,  sometimes  complicated  in  design  in  order  to  obtain  clearance 
between  parts  of  the  structure  or  apparatus. 

7  -Where  it  is  possible,  apparatus  hangers  should  rest  on  the 
members  which  support  them  and  not  depend  entirely  upon  a  vertically 
bolted  or  riveted  connection.     The  hangers  should  be  well  braced, 
especially  those  which  hang  far  below  the  underframe,  to  prevent 
swaying  of  the  apparatus,  due  to  the  motion  of  the  car.    The  hangers 
can  be  so  designed  as  to  provide  the  necessary  bracing,  but  to  accom- 
plish this  odd  shapes  are  often  required  which  increase  the  cost  of 
manufacture.     It  is  then  desirable  to  provide  hangers  and  separate 
braces  of  simple  design. 

8  When  several  switches,  fuses  and  other  electrical  apparatus  are 
required  for  the  motor,  control  and  auxiliary  circuits,  large  switch- 
board area  is  necessary,  and  in  some  instances,  the  switchboard  has 
been  installed  in  one  of  the  end  bulkheads,  occupying  most  of  the 
space  between  the  body  corner. and  door  posts.     In  recent  steel  cars, 
intermediate  body  end  posts  are  used  as  part  of  the  general  scheme 
for  anti-telescoping  provisions  at  the  end  of  the  car.     These  posts 
extend  from  the  body-end  sill  to  the  body-end  plate,  and  it  is  recom- 
mended, in  order  to  interfere  as  little  as  possible  with  the  general  anti- 
telescoping  scheme,  that  two  small  switchboards  be  used,  one  placed 
in  the  bulkhead  on  each  side  of  the  body-end  door  opening,  and  located 
as  high  above  the  platform  as  the  size  of  the  boards  will  permit.  This 
arrangement  of  switchboards  provides  for  the  use  of  short  interme- 
diate body-end  posts,  extending  upwards  from  the  body-end  sill  to  the 
horizontal  frame  member,  located  just  below  each  switchboard  and 
connected  to  the  body  corner  and  door  posts. 

9  In  wooden  car  construction  it  is  necessary  to  provide  ground 
wires  from  the  various  electrical  circuits  to  some  part  of  the  car  which 
is  a  negative  conductor.     This  is  unnecessary  on  cars  of  steel  con- 
struction, as  the  electrical  circuits  can  be  grounded  at  almost  any 
part  of  the  car  structure. 


H.  A.  CURRIE  65 

10  The  gteel  car  is  safer  than  cars  of  wood  construction,  as  there 
is  no  danger  of  bad  fires  on  account  of  short  circuits.     Parts  of  the 
structure  of  a  steel  car  will  not  become  alive,  as  is  sometimes  found  in 
cars  of  wood  construction. 

11  The  wiring  conduit  on  a  steel  car  should  be  provided  for  at 
the  time  the  car  is  being  designed.    Unless  this  is  done,  difficult  bends 
in  the  conduit  may  occur  and  it  is  sometimes  found  necessary  to  cut 
and  reinforce  the  structural  members." 


No.  1388  A 

AIR  BRAKES  FOR  HEAVY  STEEL  PAS- 
SENGER CARS 

BY  A.  L.  HUMPHREY/  WILMERDING,  PA. 
Non-Member 

Advancement  in  the  development  of  air  brakes  has  been  no  less 
contingent  upon  the  development  of  rolling  stock  than  the  economic 
handling  of  traffic  through  the  use  of  heavier  and  faster  trains  is 
contingent  upon- the  advancements  in  motive  power.  A  review  of  the 
history  of  railroad  transportation  development  in  this  country  will 
show  a  steady  and  unceasing  advance  from  year  to  year.  Equivalent 
advancement  in  the  efficiency  of  appliances  such  as  air  brakes  was 
consequently  necessary  in  order  that  the  control  and  safe  handling 
of  longer  and  heavier  trains  should  not  operate  as  a  barrier  to  these 
developments. 

2  A  brief  comparison  of  the  conditions  existing  at  the  time  of 
the  introduction  of  the  air  brake  with  the  conditions  at  present,  will 
show  that  the  advancement  in  rolling  stock  has  been  more  rapid  than 
those  who  have  not  been  in  close  touch  with  the  situation  are  likely  to 
realize.       For    example,     the    weight    on     drivers    of     high-speed 
passenger  engines  has  increased  from  25,000  to  180,000  Ib.     The 
drawbar  pull  of  locomotives  has  increased  from  7000  Ib.  to  30,000  Ib. ; 
working  steam  pressure  has  increased  from  125  Ib.  to  ,225  Ib. ;  weights 
of  passenger  cars  have  increased  from  20,000  Ib.  to  150,000  Ib.     The 
schedule  speeds  of  passenger  trains  have  increased  from  30  miles  per 
hour  to  65  miles  per  hour,  and  it  is  not  uncommon  for  speeds  to  reach 
as  high  as  85  to  90  miles  per  hour. 

3  Taking  the  average  weights  of  trains  and  average  speed  at  the 
time  the  air  brake  was  introduced  as  compared  with  the  trains  and 
speeds  of  today,  the  weight  per  vehicle  has  not  only  increased  nearly 
eight  times,  but  the  foot-pounds  of  energy  to  be  destroyed  is  nearly  15 
times  as  much.     In  order  to  meet  the  demands  of  modern  service 
conditions  as  efficiently  as  heretofore,  means  should  be  provided  for 
dissipating  the  total  energy  stored  up  in  this  swiftly  moving  mass  in 

Wice-President  and  General  Manager,  Westinghouse  Air  Brake  Company. 

Presented  at  the  New  York  Meeting,  April  1913,  of  THE  AMERICAN  SO- 
CIETY OF  MECHANICAL  ENGINEERS. 

66 


AIR  BRAKES  FOR  HEAVY  STEEL  PASSENGER  CARS  67 

at  least  as  short  a  time  and  distance  as  before.  In  fact  it  is  desirable  to 
do  this  in  as  much  less  time  as  is  consistent  with  comfort  to  passengers 
and  accuracy  of  control,  in  the  case  of  service  stops,  and  in  as  much 
shorter  distance  or  time  as  may  be  possible  in  the  case  of  emergency. 
Not  only  must  the  brake  be  automatic  in  its  operation,  but  it  must  be 
capable  at  any  time  and  under  any  conceivable  circumstances  to  pro- 
duce the  maximum  possible  retarding  force  within  as  short  a  period  of 
time  as  the  known  resources  available  and  physical  limitations  will 
permit. 

4  When  we  consider  that  it  requires  a  distance  of  8  to  12  miles 
for  a  locomotive  of  modern  design,  hauling  a  train  of  say  ten  cars, 
to  accelerate  to  a  speed  of  80  miles  per  hour  and  that  this  same  train 
should  be  brought  to  a  standstill  within  the  shortest  possible  time — 
or  say  in  one-tenth  of  the  distance  required  to  accelerate  to  this  speed 
— it  is  hardly  conceivable  that  this  can  be  done  with  the  means  avail- 
able, which  is  a  retarding  force  produced  by  frictional  contact  of  metal 
shoes  against  the  wheels,  which  is.  in  turn  limited  by  the  adhesion 
between  the  wheels  and  the  rail. 

5  This  factor,  viz.,  the  friction  obtainable  between  wheel  and  rail 
and  shoe  and  wheel  is  the  basis  on  which  we  must  start,  and  upon 
which  we  are  limited,  as  to  the  amount  of  retarding  force  obtainable. 
It  is  therefore  of  first  importance  in  designing  an  air-brake  installation 
to  give  due  consideration  to  the  contact  between  the  wheel  and  rail 
and  the  possible  efficiency  of  the  brake  shoe.     The  air  brake  in  itself 
is  practically  limitless  in  the  amount  of  force  obtainable,  but  the 
practical  application  of  this  force  is  where  the  line  must  be  drawn. 
In  this  connection  it  is  worthy  of  note  that  the  brake  shoe  today  has 
about  four  times  as  much  work  to  do  as  it  had  30  years  ago.  The  chief 
effect  of  this,  however,  is  to  destroy  the  brake  shoe  at  a  much  more 
rapid  rate,  without  permitting  any  material  lengthening  of  stopping 
distance. 

6  The  improvements  made  in  air  brakes  in  recent  years,  which 
have  made  it  possible  to  control  the  present  heavy  high-speed  passenger 
trains  with  approximately  the  same  degree  of  efficiency  as  the  older 
forms  controlled  the  equipment  of  their  day,  have  been  based  on 
scientific  principles  and  experience  in  obtaining  reliable  information 
and  data.    The  matter  of  time  of  transmission  of  compressed  air  was 
not  so  important  a  factor  with  the  shorter  trains  and  slower  speeds  as 
it  is  today,  where  a  train  running  at  80  miles  per  hour  passes  over  a 
distance  of  117  ft.  per  second;  consequently  a  few  seconds  saving  in  the 
time  of  getting  the  brakes  to  fully  apply  is  just  so  much  relative  gain 


68  A.  L.  HUMPHREY 

in  the  time  and  length  of  stop.  With  the  latest  improved  pneumatic 
equipment,  the  maximum  brake  cylinder  pressure  can  be  obtained 
throughout  a  modern  train  of  ten  cars  in  4  seconds,  which  is  the 
shortest  possible  time  that  this  can  be  obtained  by  serial  quick  action 
through  a  train  of  this  length.  For  the  purpose  of  shortening  this 
time  serious  consideration  is  being  given  by  some  railroad  officials 
to  the  type  of  brake  equipment  used  on  the  New  York  subway,  and 
known  as  the  "electro-pneumatic,"  which  would  not  only  tend  to  cut 
the  time  of  full  application  in  two,  but  by  means  of  the  electric  con- 
trol all  brakes  are  applied  simultaneously,  which  not  only  assists  in 
shortening  the  stop  but  in  preventing  shocks,  etc. 

7  Another  equally  important  factor  now  coming  more   prom- 
inently into  use  is  the  application  of  brake  shoes  to  each  side  of  the 
wheel,  known  as  clasp  brakes.     The  virtue  of  clasp  brakes,  however, 
is  not  so  much  in  the  aid  they  afford  in  shortening  the  stop  as  in  the 
equalizing  effects  of  pressure  on  the  wheels,  journal  box  bearings  and 
trucks,  the  minimizing  of  lost  motion  which  affects  the  brakes  through 
increased  piston  travel,  and  the  less  tendency  toward  wheel  sliding 
while  the  brakes  are  applied. 

8  While  a  comparison  of  the  relative  merits  of  a  brake  equip- 
ment, as  with  most  mechanical  devices,  is  frequently  based  on  their 
maximum  capacity,  it  must  be  borne  in  mind  that  an  air-brake  equip- 
ment must  be  designed  to  include  flexibility  for  service  operation,  in 
which  it  is  operated  99  per  cent  of  the  time  and  during  which  time  it 
should  be  capable  of  handling  smoothly  the  extreme  lengths  of  trains, 
while  at  the  same  time  it  must  be  capable  and  ready  under  all  conceiv- 
able circumstances  to  produce  the  maximum  permissible  braking  force 
in  case  of  an  emergency. 

9  It  is  not  especially  difficult  to  increase  the  speed  of  a  train 
from  30  to  40  miles  per  hour,  but  it  requires  a  vastly  greater  amount 
of  energy  to  increase  the  speed  from  60  to  70  miles  per  hour.    In  like 
manner,  for  any  given  increase  in  speed,  the  additional  amount  of 
work  required  of  the  brakes  increases  proportionally.     If,  therefore, 
the  brakes  for  the  heavier  trains  and  higher  speeds  of  today  permit 
of  stopping  in  about  the  same  distance  and  with  the  same  flexibility 
of  control  as  could  be  done  with  brakes  40  years  ago,  and  with  the 
trains  of  that  period,   it  is  at  least  gratifying  to   know   that   the 
advancement  made  in  this  particular  line  of  railroad  development  has 
kept  pace  as  closely  as  it  could  consistently  with  the  development  in 
transportation  facilities,  through  which  its  rate  of  advancement  is 
largely  controlled. 


No.  1388  I 

CAST-STEEL  DOUBLE  BODY  BOLSTERS, 

PLATFORMS  AND  END  FRAMES 

FOR  STEEL  CARS 

BY  C.  T.  WESTLAKE,  ST.  Louis,  Mo. 
Member  of  the  Society 

Cast  steel  as  applied  to  underframes  and  end  frames  of  railroad 
cars  is  the  result  of  careful  design  and  painstaking,  and  thorough 
development  of  the  art  of  casting  in  sand  molds.  These  large 
steel  castings  are  made  in  baked  molds,  confined  in  massive 
metal  forms,  by  a  special  method  that  assures  positively  against 
swelling  due  to  pressure  of  the  inflowing  metal,  and  yet  permits 
yielding  to  the  pressure  of  the  contracting  metal  when  cooling,  so 
that  the  castings  are  very  accurate  in  shape  and  close  to  size,  and  are 
free  from  shrinkage  stresses. 

%  ;Steel  is  an  alloy  of  iron  and  carbon  and  differs  from  other 
alloys  of  iron  by  being  capable  of  developing  all  its  physical  properties 
to  the  maximum  degree.  Its  most  distinctive  properties  are  rigidity, 
ability  to  stand  maximum  forces  without  yielding;  elasticity,  ability 
to  return  to  normal  after  being  loaded  to  deflection;  ductility,  ability 
to  stand  distortion  beyond  its  elastic  limit  without  fracture;  mallea- 
bility, permitting  it  to  be  forged ;  tensility,  high  tensile  strength ;  and 
weldability,  permitting  it  to  be  welded  by  heating  and  hammering. 
These  properties  which  steel  possesses  in  a  maximum  degree  distin- 
guish it  from  all  other  alloys  of  iron. 

3  Cast  steel  and  rolled  steel  are  produced  by  the  same  processes 
and  of  the  same  materials,  are  of  the  same  chemical  composition  and 
have  the  same  physical  properties,  and  cast  steel  may  be  substituted 
for  rolled  steel,  using  the  same  fiber  stresses,  and  its  substitution  is 
limited  only  by  the  minimum  section  that  can  be  poured  in  the  molds. 

4  As  recently  as  1893,  cast  steel  was  comparatively  unknown 
in  car  construction,  and  in  that  year  its  introduction  began  in  the 
use  of  truck  bolsters  for  freight  cars.    This  was  followed  a  few  years 
later  by  body  bolsters  or  transoms,  and  it  was  only  after  their  use  on 

Presented  at  the  New  York  Meeting,  April  1913,  of  THE  AMERICAN  SO- 
CIETY OF  MECHANICAL  ENGINEERS. 


70  CAST-STEEL  BOLSTERS,  PLATFORMS  AND  END  FRAMES 

freight  cars   had  demonstrated   satisfactorily   the   reliability   of   the 
material  and  design,  that  attention  was  turned  to  passenger  cars. 

5  The  double  body  bolster  was  first  to  receive  consideration  for 
passenger  cars,  and  although,  due  to  casting  difficulties,  its  weight  was 
at  first  excessive,  it  was  quickly  refined  and  assigned  to  its  proper 
place  with  other  cast-steel  articles.    It  was  found  to  be  so  much  lighter, 
stronger  and  permanantly  effective  than  the  built-up  type,  by  forming 
a  one-piece  cradle  or  support  for  each  end  of  the  car  body,  that  its 
use  soon  became  almost  universal  in  construction  of  passenger  cars. 

6  As  the  demand  increased  for  stronger,  safer  and  less  combus- 
tible cars,  the  problem  of  replacing  wood  with  steel  developed  many 
difficulties.     The  wooden  car  was  the  result  of  many  years  of  experi- 
menting, of  cutting  and  trying  with  a  material  easily  worked,  but  as 
one  of  the  most  valuable  properties  of  cast  steel  is  its  adaptability  to 
combining  a  multiplicity  of  complex  parts  into  a  single  one  of  simple 
form,  it  was  gradually  developed  from  the  double  body  bolster  form, 
first  to  include  end  sills,  then  end  and  buffing  sills ;  next  the  end  and 
buffing  sills  were  combined  with  longitudinal  members  extending  to, 
and  connecting  with  the  double  body  bolster.     Finally  these  parts, 
together  with  many  others  combined  into  a  single  simple  member  at 
each  end  of  the  car  underframe,  and  comprising  so  many  of  the  fixed 
parts  that  it  is  now  only  necessary  for  the  car  builder  to  connect  them 
by  center  girders  and  to  apply  draft  and  buffing  gears  and  the  super- 
structure to  complete  the  car  frame. 

7  The  ideal  underframe  should  have  all  connecting  members  in 
the  same  plane  so  as  to  avoid  buckling  due  to  eccentric  leading;  it 
should  be  so  designed  that  each  member  will  independently  perform 
its  individual  functions,  passing  the  stresses  from  one  member  to  the 
other  through  the  smallest  number  of  properly  aligned  connections; 
and  all  should  be  so  arranged  in  relation  to  each  other  as  to  form  one 
powerful,  compact,  shock-absorbing  element  throughout  the  length  of 
the  car. 

8  This  can  be   accomplished  to   great  advantage   in  cast-steel 
construction  since  the  metal  can  be  properly  distributed  in  proportion 
to  the  stresses.    The  gusset  plates  can  be  placed  in  the  same  plane  as 
the  flanges  of  intersecting  members,  and  the  whole  reduced  to  mini- 
mum weight  and  to  the  smallest  number  of  parts  with  practically  no 
joints.    It  can  be  molded  to  any  desired  conformation,  can  be  shaped 
to  any  curve,  useful  or  ornate,  without  the  use  of  expensive  dies,  can 
be  provided  with  necessary  projections  joined  to  the  main  members  by 


C.  T.  WESTLAKE  71 

proper  fillets.  Openings  may  be  provided  with  finished  and  reinforced 
edges,  and  all  parts  may  be  molded  to  symmetrical,  pleasing  contour, 
all  edges  rounded  and  a  complete,  practical,  operative  device,  eman- 
ating from  a  single  source  furnished  to  the  car  builders  ready  for 
application. 

9  As  the  rounding  of  curves  necessitates  the  use  of  convex  ends 
to  the  car  body,  the  central  portion  of  the  ends  is  most  exposed 
and  liable  to  receive  initial  impacts,  and  this  portion  should  be  made 
strongest  and  most  capable  of  properly  transmitting  the  force  of  im- 
pacts to  the  balance  of  frame. 

10  The  underframe  receives  the  force  of  end  collision  as  a  column 
load  on  its  longitudinal  members,  while  the  end  frame  receives  it  as 
a  transverse  load  on  exposed  members  supported  at  their  ends.    As  it 
is  impracticable  under  these  conditions  to  make  the  end  frame  equally 
as  strong  as  the  underframe,  provision  should  be  made  for  protecting 
the  end  frame  against  destructive  forces.     The  underframe  should  be 
arranged  so  as  to  receive  the  initial  impact,  and  if  the  encountered 
force  is  sufficient  to  destroy  it,  it  should  fail  in  such  manner  as  to 
form  additional  protection  to  the  end  frame. 

11  This  is  accomplished  in  cast-steel  construction  by  arranging 
the  parts  of  the  longitudinal  members  so  that  when  loaded  to  destruc- 
tion by  a  collision  force,  the  end  portions  yield  upwardly,  thus  folding 
the  exposed  portion  of  the  platform  up  against  the  end  of  the  car 
body,  and  forming  an  addition  to  the  end  frame  to  assist  in  distribu- 
ting the  force  to  all  the  longitudinal  members  of  the  superstructure. 
The  advantage  of  this  construction  has  been  demonstrated  in  wrecks 
when  this  identical  action  has  taken  place,  the  safety  of  passengers 
assured,  and  the  property  loss  kept  low. 

12  The  cast-steel  platform  as  now  provided  for  blind  end  cars, 
comprises  the  buffing  sill  having  recesses  for  the  buffer  foot  plates, 
holes  and  brackets  for  the  buffer  stems,  pockets  for  the  buffing  device, 
brackets  for  safety  chains,  lugs  for  draft  gear,  brackets  for  drawbar 
carry  irons,  anti-telescoping  plate,  extensions  of  the  center  sills  and 
bottom  chords  of  the  side  sills,  all  of  the  double  body  bolster  members 
including  side  bearing  arches  and  extending  for  a  distance  of  over 
14  ft.  inward  from  the  end  of  the  car  to  a  point  considerably  back 
of  the  truck  center,  and  counting  rivets,  gusset  plates  and  connecting 
angles,  combining  more  than  1000  pieces  into  a  single,  powerful, 
shock-absorbing  element  of  less  weight  than  fabricated  material  of 
the   same   strength. 


72  CAST-STEEL  BOLSTERS,  PLATFORMS  AND  END  FRAMES 

13  The  cast-steel  platform  and  double  body  bolster  for  vestibule 
cars  comprises  all  the  parts  enumerated  for  blind  end  cars,  and  in 
addition,  includes  the  exposed,  platform  longitudinal  members,  step 
risers  and  end  sill,  measures  over  17  ft.  in  length,  is  made  of  a  single 
piece,  and  is  also  of  less  weight  than  fabricated  material  of  the  same 
strength. 

14  Since  the  government  has  taken  a  hand  in  the  construction  of 
cars  used  in  its  service,  stronger  body  end  frames  are  being  used,  and 
as  the  end  of  the  car  is  the  first  to  encounter  end  collision  forces,  it 
reasonably  deserves  closer  and  more  careful  consideration. 

15  Most  damage  is  produced  by  end  collisions  and  to  protect  life 
and  property  from  them,  the  colliding  object  must  be  prevented  from 
entering  the  car.    To  accomplish  this,  the  end  frame  and  end  portion 
of  underframe  should  be  constructed  so  as  to  distribute  the  force  of 
collision  into  all  the  longitudinal  members  of  the  car,  passing  it  into 
the  largest  mass,  utilizing  every  particle  of  available  inertia  to  absorb 
the  force  without  permitting  it  to  reach  and  act  upon  the  contents 
or  occupants  of  cars. 

16  The  end  frame  proper  should  be  designed  so  that  when  a 
single  member  is  loaded,  all  will  act  with  it,  and  this  can  be  accom- 
plished only  by  connecting  them  so  as  to  form  a  single  mass,  and  best 
by  forming  them  in  a  single  piece  as  in  cast-steel  construction. 

17  In  designing  the  cast-steel  end  frame  we  assume  it  to  be  a 
beam  supported  at  its  upper  and  lower  ends  and  loaded  at  a  point 
about  18  in.  above  its  lower  end.     We  provide  connections  between 
the  end  frame  and  balance  of  car  frame  of  sufficient  value  to  develop 
the  full  transverse  strength  of  the  end  frame;  the  vertical  members 
of  end  frame  are  connected  by  horizontal  members  so  that  in  case  the 
end  frame  is  loaded  to  destruction  the  connections  are  sufficient  to 
disrupt  all  the  longitudinal  members  of  the  car  frame,  and  when  they 
yield  all  parts  will  be  forced  toward  the  center  of  the  end  of  the  car 
and  tend  to  prevent  one  car  telescoping  the  other. 

18  Cast-steel  parts  weigh  less  than  built-up  members  carrying 
the  same  load  since  the  metal  in  castings  can  be  properly  distributed 
in  proportion  to  stresses.    In  built-up  construction  the  metal  overlaps 
at  the  joints  and  this,  together  with  the  rivet  heads,  makes  an  ad- 
ditional weight  which  in  cast  construction  is  avoided.    In  the  latter, 
reliance  is  placed  in  a  single  solid  member  and,  as  there  are  no  joints, 
there  is  no  chance  of  their  being  imperfect  or  becoming  loose. 

19  The  advantage  in  cast  steel  to  the  car  builder  is  also  very 


C.  T.  WESTLAKE  73 

great.  To  produce  a  platform  of  the  built-up  type  at  least  eight 
different  classes  of  material  are  required.  This  comes  from  eight 
different  manufacturers,  frequently  from  as  many  different  points  of 
production,  much  of  it  in  less  than  car  load  lots,  and  all  has  to  be 
requisitioned,  purchased,  received,  stored  and  recorded  for  use  on  each 
particular  lot,  and  in  order  to  reduce  storage  space  and  avoid  con- 
gestion in  the  car  plant,  all  deliveries  have  to  be  carefully  and  ac- 
curately timed,  and  followed  up.  Then  each  material  has  to  be  passed 
through  the  different  departments  of  the  car  plant  to  be  cut,  shaped, 
punched,  drilled  and  the  same  timing  and  tracing  methods  used,  so 
as  to  have  all  parts  completed  at  the  proper  time.  When  cast  steel  is 
used  but  one  material  is  purchased  from  a  single  plant,  only  one  piece 
is  handled,  that  in  car  load  lots,  and  when  it  arrives  it  is  immediately 
ready  and  available  for  application  without  storage  or  re-handling, 
facilitating  completion  of  the  car  by  leaving  more  car  plant  machinery 
available  for  other  work. 

,20  A  plant  capable  of  producing  castings  of  this  nature  in 
quantities  to  meet  requirements  of  the  many  car  plants  must  have 
buildings  of  extensive  area  and  equipment  in  proportion,  as  it 
ordinarily  requires  about  ten  days  for  a  casting  to  pass  through  the 
various  processes  of  casting,  cooling,  roughing,  cleaning  and  ma- 
chining, and  an  accumulation  of  ten  days'  output  has  to  be  constantly 
accommodated.  All  handling  and  conveying  apparatus  must  be  in 
duplicate  so  as  to  insure  uninterrupted  operation  and  machines  for 
finishing  must  be  of  the  highest  grade  and  maintained  in  perfect  con- 
dition to  produce  accurate  and  proper  results. 

21  In  car  construction  cast  steel  stands  preeminent  as  the  best 
material  for  reducing  to  the  minimum  the  weight  and  number  of  parts 
while  maintaining  requisite  strength  and  other  essential  properties, 
and  its  popularity  and  use  will  proportionately  increase  as  its  benefits 
and  advantages  become  more  generally  recognized. 


No*  1388  m 

SPECIAL  ENDS  FOR  STEEL  PASSENGER 

CARS 

BY  H.  M.  ESTABROOK,    DAYTON,  O. 
Member  of  the  Society 

After  the  passenger  car  had  emerged  from  the  stage-coach  type 
of  construction  the  box-like  shape  of  car  was  introduced  with  straight 
longitudinal  floor  sills  and  with  straight  vertical  side  and  end  posts. 
These  members  were  of  wood,  the  ends  of  the  longitudinal  floor  sills 
being  tenoned  into  mortises  in  the  wooden  end  sills.  The  vertical 
side  and  end  posts  were  in  like  manner  tenoned  into  the  side  and  end 
sills  at  their  lower  end  and  likewise  into  the  wooden  side  and  end 
plates  at  their  upper  ends.  These  side  and  end  posts  were  maintained 
in  their  several  positions,  by  wooden  spacing  blocks  or  bridging,  and 
the  whole  structure  tied  together  by  means  of  iron  rods  and  bolts. 
These  spacing  blocks  served  further  the  double  purpose  of  affording  a 
foundation  for  securing  the  outside  panels  and  the  wooden  interior 
finish. 

8  Several  types  of  roof  were  quite  prevalent  in  early  passenger 
car  days,  among  them  being  the  round  top  or  omnibus  roof,  which  has 
again  made  its  appearance  in  steel  passenger  cars  in  some  parts  of  our 
country.  Another  type  of  roof  was  the  Ogee,  or  turtle-back,  and  later 
came  the  monitor,  or  raised  deck  roof.  The  prevailing  type  of  hood 
projection  over  the  platforms  was  the  "duck's  bill"  type,  as  illustrated 
in  Fig.  1,  which  also  furnishes  a  good  idea  of  the  framing  employed 
in  those  days.  Fig.  2  shows  end  framing  of  these  same  cars. 

3  A  little  later  the  projecting  platform  hood  was  changed  from 
the  "duck's  bill"  type  to  the  bull-nose  type.  Figs.  3  and  4  show  re- 
spectively a  longitudinal  section  and  exterior  of  these  cars.  Fig.  5 
shows  the  end  construction  and  Fig.  6  the  standard  framing  employed 
in  the  first  bull-nose  hood  cars  in  the  early  eighties.  Up  to  the  middle 
eighties  no  systematic  attempt  had  been  made  to  strengthen  the  ends 
of  cars.  The  platform  members  were  all  of  wood  and  the  end  framing 
of  the  car  had  not  experienced  much  change  in  the  way  of  strength- 


Presented  at  the  New  York  Meeting,  April  1913,  of  THE  AMERICAN  SO- 
CIETY OF  MECHANICAL  ENGINEERS. 

74 


H.  M.  ESTABROOK 


75 


FIG.  1     "DUCK'S  BILL"  TYPE  OP  HOOD  PROJECTION  OVER  PLATFORMS 


.sssS^I^^^HSrSgsssss^ 


FIG.  2     END  FRAMING  FOR  " DUCK'S  BILL"  HOOD  PROJECTION 


76 


SPECIAL  ENDS  FOR  STEEL  PASSENGER  CARS 


I 


FIG.  3     SECTION  OF  BULL-NOSE  TYPE  OF  CAR 


FIG.  4     BULL-NOSE  TYPE  OF  CAR,  FRAMING  EXPOSED 


H.  M.  ESTABROOK 


77 


ening  from  the  earlier  types.  With  the  advent  of  the  narrow  vestibule 
in  1887,  which  was  immediately  followed  by  the  broad  vestibule  in 
1888,  came  the  demand  for  a  stronger  end. 

4  About  the  year  1890  there  was  brought  into  use  what  was 
known  as  an  "anti-telescoping"  end  framing.  This  construction  con- 
sisted of  double  side  and  end  sills  with  a  steel  plate  8  in.  by  %  in. 
from  18  to  24  ft.  long,  sandwiched  into  the  double  side  sill,  with  the 
end  of  these  plates  turned  so  as  to  form  a  foot  against  the  end  sill. 
The  double  end  sill  had  a  steel  plate  8  in.  by  %  in.  and  the  length 
the  width  of  the  car,  sandwiched  into  the  end  sill.  The  end  posts  of 


P^^^T  p_iij 

FIG.  5    END  CONSTRUCTION  OF  BULL-NOSE  TYPE  OF  CAR 

the  car  were  reinforced  by  steel  bars  3%  in-  by  %  in.,  extending 
downward  through  and  bolted  through  the  sandwiched  end  sill  and 
having  their  upper  ends  extending  upward  and  bearing  on  and  bolted 
through  a  steel  plate  6  in.  by  %  in.,  which  was  bolted  to  the  oak  end 
plate  of  the  car.  This  stiffening  plate  extended  across  the  width  of 
the  car  and  the  ends  of  the  steel  plate  being  turned  so  as  to  form  a 
foot  upon  the  side  plate  of  the  structure.  This  anti-telescoping  con- 
struction is  illustrated  in  Fig.  7.  This  design  of  end  framing  came 
into  general  use  throughout  the  country  and  is  in  use  today  in  the 


78  SPECIAL  ENDS  FOR  STEEL  PASSENGER  CARS 

majority  of  wooden  passenger  cars  built  since  1890.  It  is  interesting 
to  note  that  this  anti-telescoping  framing  is  the  same,  with  some 
modifications  and  additions,  as  was  adopted  by  the  United  States 
Government  for  the  construction  of  full  postal  cars  and  known  as 
Specification  No.  1. 

5  Somewhat  later  this  type  of  end  framing  was  elaborated  upon 
by  the  use  of  a  heavy  steel  angle  flitched  into  the  end  sill,  with  the 
end  still  further  reinforced  by  a  20  in.  by  y2  in.  steel  gusset  plate  on 
the  under  side  of  the  sills,  and  by  the  use  of  steel  Z-bars  in  the  end 
posts  and  a  heavy  steel  angle  introduced  into  the  construction  of  the 
end  plate  of  the  car. 

6  The  increased  weight  of  the  vestibules  and  anti-telescoping  end 
framing  developed  the  necessity  for  a  stronger  platform  construction 
than  the  old  style  wooden  platform  member  that  had  been  used  for 
many  years.     About  the  year  1895  the  standard  steel  platform,  com- 
posed of  steel  I-beams,  came  into  general  use,   and  was  employed 
continuously  until  the  advent  of  the  steel  car  superseded  it  by  other 
designs. 

7  Notwithstanding  the  frantic  efforts  of  Congress  toward  the 
general  adoption  of  steel  passenger  cars,   it  has  been  stated  upon 
reliable  authority  that  no  vestibuled  wooden  passenger  car,  in  the  con- 
struction of  which  was  employed  the  anti-telescoping  end  framing, 
in  a  straight-on  end  to  end  collision  (although  frequently  having  the 
ends  concaved)  has  ever  had  the  end  crushed  in  to  the  extent  of  the 
adjoining  car  body  telescoping  and  entering  it. 

8  The  United  States  Government  in  seeking  to  strengthen  the 
end  construction  of  postal  cars  adopted  this  form  of  anti-telescoping 
end  framing  with  the  addition  of  two  7-in.,  23.46-lb.  steel  bulb  beams 
on  either  end  of  the  car.    These  bulb  beams  have  their  flat  base  resting 
against  the  outside  of  the  reinforced  end  posts  of  the  car,  being  located 
in  line  with  and  immediately  behind  the  vestibule  diaphragms  and 
face  plate.     At  its  lower  end,  this  bulb  beam  'has  the  head  and  web 
notched  out  with  the  base  flange  extending  downward  through  the 
flitched  end  sill,  the  main  body  of  the  beam  resting  upon  the  1  in. 
thick  steel  plate  on  top  of  the  buffer  beam.     At  the  upper  end  these 
bulb  beams  have  the  web  and  bulb  head  sheared  diagonally  so  the  base 
flange  extends  upward  on  the  outside  of  the  end  plate  of  the  car 
framing,  and  through  this  flange  passes  the  top  piston  stems  of  the 
vestibule  mechanism.     This  type  of  construction  is  now  obsolete  in 
postal  cars,  Congress  having  enacted  a  law  requiring  them  to  be  of 
steel  construction. 


H.  M.  ESTABROOK 


79 


80 


SPECIAL  ENDS  FOR  STEEL  PASSENGER  CARS 


9  When  the  steel  passenger  car  made  its  appearance  about  the 
year  1905,  the  passenger  car  entered  a  period  of  transition  and  evolu- 
tion from  which  it  has  not  yet  entirely  emerged  with  a  recognized 
standard  form  of  construction.  The  wooden  car  had  attained  a  degree 
of  uniformity  that  established  it  as  an  accepted  standard.  In  the 


FIG.  7    ANTI-TELESCOPING  IRON  END  FRAMING 


construction  of  the  early  steel  passenger  cars,  as  was  probably  natural, 
an  attempt  was  made  to  follow  closely  the  lines  employed  in  the  con- 
struction of  wooden  cars,  with  the  result  that  the  first  steel  cars  were 
inferior  in  strength  'of  end  construction  to  the  prevailing  wood  con- 
struction, but  the  evolution  has  been  rapid,  one  improvement  following 


H.  M.  ESTABROOK 


81 


close  upon  the  heels  of  another.  In  the  entire  history  of  car  building, 
there  has  probably  not  been  devoted  so  much  concentrated  thought 
and  study  to  the  improvement  in  design,  by  the  most  expert  engi- 
neering talent  of  the  railroads  and  car  builders,  as  has  been  shown 
since  the  introduction  of  steel  cars.  This  has  resulted  in  rapid  im- 
provement of  end  construction  until  we  have  today  reached  a  design 


-9-8  OYGI\  fasts 


FIG,  8     BODY  END  FRAMING,  TYPE  SHOWN  IN  FIG.  9 


that  is  considered  practically  standard.  This  development  has  no 
doubt  been  hastened  by  the  action  of  Congress  relative  to  steel  postal 
cars  and  the  cooperation  of  committees  of  the  railway  mail  service, 
the  railroads  and  the  car  builders,  to  the  end  that  a  standard  specifi- 
cation for  the  strength  of  the  various  parts  of  the  car,  and  especially 


82 


SPECIAL  ENDS  FOR  STEEL  PASSENGER  CARS 


H.  M.  ESTABROOK  83 

the  end  construction,  has  been  adopted  by  the  Postoffice  Department 
in  which  it  is  provided  that: 

The  maximum  end  shock  due  to  buffing  shall  be  assumed  as  a  static  load 
of  400,000  Ib.  applied  horizontally  at  the  resultant  line  of  forces  acting  as  the 
center  line  of  the  buffing  mechanism  and  at  the  center  line  of  draft  gear, 
respectively,  and  shall  be  assumed  to  be  resisted  by  all  continuous  longitudinal 
underframe  members  below  the  floor  level,  provided  such  members  are  suffi- 
ciently tied  together  to  act  in  unison. 

The  sum  of  the  section  moduli  of  all  vertical  end  members  at  each  end  shall 
be  not  less  than  65  and  the  section  moduli  of  the  main  members,  either  form- 
ing or  adjacent  to  the  door  posts,  shall  be  not  less  than  75  per  cent,  of  this 
amount.  The  horizontal  reactions  of  all  vertical  end  members  at  top  and 
bottom  shall  be  calculated  from  an  assumed  external  horizontal  force,  applied 
18  in.  above  the  floor  line,  to  all  vertical  members  in  the  proportions  given, 
such  force  being  of  sufficient  amount  to  cause  bending  of  all  vertical  members 
acting  together,  and  top  and  bottom  connections  of  vertical  members  shall  be 
designed  for  these  reactions.  Except  where  vertical  end  members  shall  bear 
directly  against  or  be  attached  directly  to  longitudinal  members  at  either  top  or 
bottom,  the  assumed  reactions  shall  be  considered  as  loads  applied  to  whatever 
construction  is  used  at  end  sill  or  end  plate  and  both  these  last  named  mem- 
bers shall  have  section  moduli,  respectively,  sufficient  to  prevent  their  failure 
horizontally  before  that  of  the  vertical  end  members.  All  parts  of  the  car 
framing  shall  be  so  proportioned  that  the  sum  of  the  maximum  unit  stresses 
to  which  any  member  is  subject  shall  not  exceed  the  following  amounts  in 
pounds  per  square  inch — these  stresses,  unless  otherwise  stated  below,  are  for 
steel  having  an  ultimate  tensile  strength  of  from  55,000  to  65,000  Ib.  per  sq.  in. : 

Bolsters  of  Eolled  Steel — Stress  shall  not  exceed  12,500  Ib.  per  sq.  in. 

Sills  and  Framing  of  Eolled  Steel — Stress  shall  not  exceed  16,000  Ib.  per 
sq.  in. 

When  cast  steel  is  used  the  allowable  stresses  may  be  the  same  as  for  rolled 
steel  except  tension  stresses,  which  must  be  at  least  20  per  cent  less  than  those 
allowed  for  rolled  steel,  as  specified  above. 

10  To  meet  these  requirements,  there  are  at  this  time  three 
distinct  forms  of  construction  employed :   The  one  most  generally  em- 
ployed is  illustrated  in  Figs.  8  and  9,  which  is  composed  of  rolled-steel 
sections  with  the  center  sills  running  the  full  length  of  the  car  from 
buffer  beam  to  buffer  beam.    Another  type  is  that  in  which  the  rolled 
steel  center  sills  connect  at  the  bolster  with  a  steel  casting,  forming 
a  combined  body  bolster,  center  and  side  sills,  and  end  sills,  as  illus- 
trated in  Figs.  10  and  11.    Another  type  is  that  in  which  the  rolled- 
steel  center  sills  connect  at  the  bolster  with  a  steel  casting,  forming  a 
combined  body  bolster,  center  and  side  sills,  end  sill  and  the  entire 
end  frame  of  the  car,  as  illustrated  in  Fig.  12. 

11  In  the  first  form  of  construction,  shown  in  Figs.  8  and  9, 
rolled  sections   are  employed   entirely.     The  members  forming  the 


84  SPECIAL  ENDS  FOR  STEEL  PASSENGER  CARS 

center  sill  construction  extend  the  full  length  of  the  car  from  one 
buffer  beam  to  the  other  and  all  other  longitudinal  members,  such  as 
side  sills,  belt  rail,  etc.,  extending  the  full  length  of  the  car  body 
and  in  the  case  of  vestibuled  cars,  the  rolled  section  side  plate  extends 
the  full  length  of  the  car  from  one  vestibule  corner  post  to  another. 
The  end  sill  is  usually  composed  of  pressed  or  rolled  shapes  riveted 
to  the  center-sill  construction  and  extending  laterally  outwards  to  the 
sides  of  the  car,  the  ends  of  the  side-sill  members  butting  against  and 
being  riveted  to  these  end-sill  members.  The  upper  end  plate  of  the 
car  is  composed  of  rolled  or  pressed  sections  extending  in  one  piece 
across  the  width  of  the  car  and  attached  to  the  longitudinal  side  plates 
by  connecting  angles  and  gussets.  To  this  end  plate  are  also  attached 
the  longitudinal  members  of  the  upper  deck  sides.  The  end  posts  are 
rolled  or  pressed  sections,  usually  Z-sections,  extending  downward  to 
the  bottom  line  of  and  riveted  to  the  end  sill.  The  upper  ends  of 
these  posts  extend  upwards  to  the  top  line  of  and  are  riveted  to  the 
end  plate.  The  nose  piece  or  buffer  beam  is  composed  of  rolled 
channels  with  their  flanges  turned  inwardly  towards  each  other,  pre- 
senting their  smooth  surfaces  on  the  outside,  these  channels  being 
formed  to  suit  the  contour  requirements  of  the  vestibule,  the  channel 
members  forming  a  box  construction  with  top  cover  plates. 

1,2  This  buffer  beam  extends  across  and  is  riveted  to  the  outward 
ends  of  the  center-sill  construction,  from  which  it  will  be  observed 
that  the  purpose  of  this  design  is  to  transmit  the  end  buffing  shock  to 
the  center-sill  construction.  The  vestibule  corner  posts  are  rolled 
channel  or  Z-sections,  whose  bottom  ends  extend  down  into  and  are 
riveted  to  the  outer  ends  of  the  buffer  beams  and  whose  upper  ends 
are  riveted  to  the  vestibule  end  plate  and  to  the  upper  longitudinal 
side  plate  of  the  car  body,  which  projects  beyond  the  end  of  the  car 
body  to  meet  and  to  connect  with  this  vestibule  corner  post.  The 
center  vestibule  posts  are  6-in.  I-beams  whose  lower  ends  extend  down- 
ward through  and  are  connected  to  the  buffer  beam  member  and 
whose  upper  ends  extend  upward  to  and  are  connected  to  the  vestibule 
end  plate  steel  angle.  Between  the  upper  ends  of  these  center  vestibule 
posts  and  the  end  of  the  car  body,  are  longitudinal  compression  mem- 
bers in  the  form  of  steel  channels  or  angles.  These  rolled  section 
corner  posts,  door  posts  and  vestibule  door  and  corner  posts,  arc, 
encased  in  light  steel  casings  formed  to  give  them  the  finished  ap- 
pearance of  the  same  members  in  a  wooden  car. 

13     In  stub-end  cars  of  this  type  of  construction,  the  buffer  beam 


H.  M.  ESTABROOK 


85 


is  of  considerably  heavier  construction  than  in  the  vestibule  car,  and 
is  usually  composed  of  a  built-up  box  construction  or  a  one-piece  steel 
casting,  this  buffer  beam  being  secured  immediately  to  the  outside 
face  of  the  end  sill.  In  this  construction  there  is  usually  employed  a 


-4-7^''-  —>|<-—  ff|*-->| 

FIG.  10    BODY  END  FRAMING,  TYPE  SHOWN  IN  FIG.  11 

much  heavier  vestibule  center  post  than  in  the  vestibuled  car.  These 
vestibule  posts,  usually  being  a  12-in.  I-beam,  are  located  immediately 
in  line  with  and  behind  the  vestibule  diaphragm  and  face  plate.  The 
end-post  construction  is  much  the  same  as  described  for  the  vestibuled 
car,  there  being  a  difference,  however,  in  the  construction  of  the  end 
plate,  which  in  the  stub-end  car  is  a  pressed  channel  section  formed 


86 


SPECIAL  ENDS  FOR  STEEL  PASSENGER  CARS 


H.  M.  ESTABROOK 


87 


to  suit  the  contour  of  the  car  end,  this  channel  end  plate  being  placed 
across  the  end  of  the  car  in  a  horizontal  plane,  and  into  and  riveted 
to  this  channel  end  plate  are  the  upper  ends  of  the  corner  posts,  end 
posts  and  vestibule  posts. 

14  In  the  second  type  of  construction  referred  to,  a  steel  casting 
is  employed  forming  the  body  bolster  and  platform  to  which  the  center- 
sill  construction  is  riveted  to  this  steel  bolster.  This  construction  is 
illustrated  in  Figs.  10  and  11,  from  which  it  will  be  observed  that  the 
center  sill  construction,  the  end  sill,  platform  and  buffer  beam  are  all 
embodied  in  one  steel  casting.  The  end-post  construction,  the  corner 
posts,  vestibule  corner  and  center  posts  are  practically  of  the  same 


FIG.  12     INTEGRAL  STEEL  CASTING  USED  IN  END  FRAME  CONSTRUCTION 


construction  as  described  for  the  built-up  type,  the  difference  being  in 
the  method  of  attaching  the  lower  ends  of  these  posts.  The  steel 
eastings  have  openings  or  pockets  in  the  end  sill  and  buffer  beam  mem- 
bers, in  which  the  lower  ends  of  these  posts  rest  and  are  riveted  to  the 
casting.  The  construction  of  the  end  of  the  car  body,  the  vestibule 
and  hood  are  substantially  as  described  for  the  built-up  construction. 

15  This  type  of  construction  for  the  stub-end  car  is  substantially 
the  same  as  that  just  described,  the  exception  being  that  the  steel 
bolster  and  end-sill  casting  takes  the  place  of  the  built-up  type  of 
center  and  end-sill  construction,  the  end  post,  corner  post  and  upper 
end  construction  being  identical  in  the  two  types. 

16  In  the  third  type  of  construction  referred  to  the  entire  bottom 
framework  of  the  car  from  the  bolster  outward  to  the  platform  and 


88 


SPECIAL  ENDS  FOR  STEEL  PASSENGER  CARS 


buffer  beam,  is  one  integral  steel  casting,  and  the  entire  end  framing 
of  the  car  is  one  integral  steel  casting,  as  illustrated  by  Fig.  12. 

17     In  referring  to  the  three  types  of  construction  just  outlined, 


FIG.  13     COLLAPSIBLE  VESTIBULE  CONSTRUCTED  ENTIRELY  OF  STEEL 


it  must  be  understood  that  reference  is  made  to  them  only  as  types, 
and  no  attempt  is  made  to  describe  the  construction  of  any  one  rail- 
road or  car  builder  in  particular,  or  to  undertake  to  establish  any  of 


H.    M.    ESTABROOK 


89 


the  forms  described  as  being  a  standard,  as  the  details  of  construction 
vary  to  a  considerable  degree  with  different  railroads  and  builders. 
18     It  is  of  course  apparent  that  the  weight  of  the  steel  car  is 


Ufel 


FIG.   14    COLLAPSIBLE  VESTIBULE  MADE  OF  A  SERIES  OF  WOODEN  POSTS  TO 
SECURE  ADVANTAGE  OF  ELASTIC  AND  CUSHIONING  PROPERTIES  OF  WOOD 


much  greater  than  a  car  of  the  same  size  of  wooden  construction,  and 
that  the  wooden  car  possesses  in  itself  a  natural  elasticity  to  absorb 


90 


SPECIAL  ENDS  FOR  STEEL  PASSENGER  CARS 


buffing  shocks  such  as  are  produced  by  collision  that  the  steel  car  does 
not  furnish.  Hence,  in  the  development  of  the  steel  car,  with  the 
enormous  increase  in  weight  of  trains  and  the  high  speed  at  which 
they  run,  there  has  been  a  growing  tendency  to  increase  the  strength 
of  the  structure  with  the  view  of  making  it  as  nearly  indestructible  as 
possible  in  order  to  compensate  for  the  absence  of  elasticity.  It  is 
also  apparent  that,  notwithstanding  the  strength  of  the  structure,  if 
it  encountered  an  opposing  force  of  sufficient  magnitude,  it  might  be 
annihilated,  and  so  this  strengthening  process,  and  the  increasing 


FIG.  15     SKELETON  OF  PLATFORM  MEMBERS  FOR  ALL-STEEL  CONSTRUCTION 


weight  and  speed  might  go  on  indefinitely  without  furnishing  the 
result  sought  for.  It  is  equally  true  that  if  the  structure  is  designed 
for  such  strength  as  to  be  indestructible,  when  the  two  opposing 
forces  meet,  the  movable  objects  within  the  cars,  which  is  the  human 
load,  must  suffer  the  damage.  To  avoid  this  possibility  the  idea  has 
been  evolved  to  construct  that  portion  of  the  end  of  the  car  between 
the  end  of  the  main  body  and  the  vestibule  face  plates,  these  members 
being  all  such  parts  as  are  embraced  in  the  platform,  vestibule  and 
hood  covering  the  vestibule,  so  that  it  will  collapse  under  a  less  shock 
than  would  be  required  to  crush  in  the  end  of  the  car  body  itself. 


H.  M.  ESTABROOK 


91 


19  This  idea  is  based  on  the  theory  that  in  a  train  in  which  there 
are  say  ten  vestibuled  cars,  there  is  the  space  between  the  main  bodies 
of  each  two  coupled  cars  occupied  by  the  platforms  and  vestibules  of 
approximately  8  ft.,  or  in  a  ten-car  train  a  space  of  approximately 
80  ft.,  of  shock  absorbing  space,  which,  if  properly  utilized  in  the 
instant  of  collision,  would  remove  to  a  large  degree  the  shock  and 
resultant  damage  to  the  car  body  itself  and  likewise  lessen  the  possi- 
bility of  damage  to  the  persons  of  the  passengers.  From  this  idea  has 
developed  what  is  termed  a  collapsible  vestibule.  It  is  generaly  con- 
ceded that  if  two  vestibuled  cars  coupled  together  could  maintain  their 


FIG.  16    SKELETON  OF  PLATFORM  MEMBERS,  STEEL  AND  WOOD  CONSTRUCTION 

respective  horizontal  planes  at  the  instant  of  shock  due  to  collision, 
there  could  be  no  telescoping  and  that  telescoping  is  due  to  one  car 
assuming,  at  the  instant  of  collision,  a  higher  or  lower  horizontal 
plane  than  its  adjoining  neighbor,  causing  one  to  ride  the  other  with 
the  resultant  telescoping  effects. 

20  It  is  generally  conceded,  that  in  cases  of  two  cars  tending  to 
telescope,  the  point  of  maximum  shock  is  never  over  20  in.  above  the 
floor  line.  In  the  Government  postal  car  specifications,  this  point  has 
been  definitely  fixed  at  18  in.  above  the  floor  line,  and  with  this  in 
view  the  end  posts  are  reinforced  for  a  distance  of  about  4  ft.  above 
the  floor  line  by  steel  angles  riveted  to  the  Z-bar  end  posts. 


92  SPECIAL  ENDS  FOR  STEEL  PASSENGER  CARS 

21  A  general  idea  of  this  collapsible  vestibule  is  afforded  by  Figs. 
13  and  14.  Fig.  13  shows  the  construction  entirely  of  steel,  while 
Fig.  14  shows  a  series  of  wooden  posts  and  platform  and  vestibule 
members  in  addition  to  the  steel  members  to  secure  the  recognized 
advantage  of  the  elastic  and  cushioning  properties  of  the  wood. 

,2-2  In  this  construction  the  longitudinal  sills  and  floor  members 
are  designed  to  stop  at  the  end  sill  of  the  car  body  proper,  the  end  of 
which  is  sheathed  with  a  heavy  steel  plate  extending  in  one  piece 
vertically  from  the  roof  downward  to  the  bottom  of  the  end  sill.  If 
the  shock  of  collision  is  not  entirely  absorbed  by  the  vestibule  members 
before  the  end  of  the  car  body  proper  can  be  crushed,  this  plate  will 
tend  to  pull  the  roof  downward  and  cause  the  direction  of  the  on- 
coming car  to  deflect  obliquely  upwards  instead  of  the  two  cars 
telescoping.  Further  to  offset  the  effect,  should  the  two  cars  change 
their  horizontal  planes  in  collision,  pressed  steel  shapes  in  the  nature 
of  anti-climbers  are  placed  below  the  buffer  beam  and  platform. 

23  Fig.  15  shows  the  skeleton  of  the  platform  members  for  the 
all-steel  construction,  and  Fig.  16  shows  the  skeleton  of  the  platform 
members  where  wooden  features  are  employed. 

24  The  vestibule  diaphragm  posts  are  constructed  of  heavy  steel 
I-beams  rigidly  secured  at  the  bottom  to  the  buffer  beam  and  at  the 
top  to  the  vestibule  end  plate  and  longitudinal  braces. 

25  The  platform,  vestibule  and  hood  members  are  designed  with 
a  view  to  withstanding  all  shocks  incident  to  regular  service,  but  in 
abnormal  shocks,  such  as  would  result  from  collision,  the  rivets  con- 
necting the  various  members  would  shear  off  with  the  exertion  of  less 
energy  than  would  be  required  to  crush  the  end  of  the  car  body, 
thereby  causing  the  vestibule  to  collapse,  absorbing  the  shock  and 
furnishing  a  cushion  between  the  two  car  bodies  proper.     It  is  as- 
sumed that  in  case  of   a   collision  these  would  be  the  only   parts 
seriously  damaged,  and  the  car  could  be  repaired  and  replaced  in 
service  with  a  minimum  of  expense  and  delay. 

26  The   entire   collapsible   vestibule,    comprising   the   platform, 
vestibule  and  hood,  is  constructed  as  a  unit,  detachable  and  separate 
from  the  car  body  proper  and  can  be  applied  after  the  car  is  built  or 
in  the  alteration  of  cars  already  built  and  is  equally  applicable  to  cars 
of  either  steel  or  wood  construction. 

27  The  object  of  the  collapsible  vestibule  is,  first,  to  protect  the 
lives  of  the  passengers  and  secondly  to  protect  the  body  proper  of  the 
car  from  serious  damage. 


ISTo.  1388  n 

DISCUSSION  ON  STEEL  PASSENGER  CAR 

DESIGN 

GEORGE  GIBBS.  On  this  occasion  when  the  subject  of  steel  pas- 
senger car  design  is  under  discussion,  it  may  be  of  interest  to  make  a 
brief  reference  to  the  early  history  of  this  important  innovation  in 
railway  operation  which  had  its  origin  in  connection  with  the  provision 
of  car  equipment  for  the  first  rapid  transit  subway  in  the  City  of 
New  York.  The  writer  was  at  that  time  consulting  engineer  of  the 
subway  construction  company  in  charge  of  car  design  and  construc- 
tion. It  was  obvious  that  the  exacting  requirements  of  the  con- 
templated service,  which  involved  tunnel  operation  at  a  high  schedule 
speed  with  closely  spaced  trains  crowded  with  passengers,  must  be 
conducted  with  all  possible  precaution  against  accident  and,  further, 
in  a  way  such  as  to  minimize  the  fatal  consequences  of  any  accident 
which  might  occur  in  spite  of  such  precautions.  The  two  consequences 
most  to  be  feared  from  an  accident  are  the  breaking  up  of  the  cars 
in  the  train  and  the  setting  of  a  fire  in  the  wreckage;  on  an  open 
railway  line  the  consequences  of  these  are  serious  enough,  but  in  a 
subway  or  tunnel  they  are  potentially  much  worse,  because  of  the 
confined  space  which  prevents  the  prompt  escape  of  passengers  from 
the  wreckage. 

Cars  for  such  service,  therefore,  should  be  protected  in  an  unusual 
degree  against  the  possibility  of  telescoping  in  an  accident,  and  the 
electric  apparatus  should  be  installed  in  such  a  way  as  absolutely  to 
prevent  the  setting  of  fires.  Incombustible  metal  cars  were  naturally 
suggested  as  the  solution  of  the  problem,  but  in  the  latter  part  of 
1901,  when  the  question  of  car  design  was  taken  up  for  the  subway, 
it  seemed  impracticable  to  consider  the  adoption  of  an  all-steel  car 
for  the  large  amount  of  equipment  required,  because  of  the  fact  that 
no  practical  steel  passenger  cars  had  ever  been  constructed  and  it  was 
evident  that  to  develop  a  serviceable  type  a  number  of  very  serious 
mechanical  problems  had  to  be  attacked  by  thorough  study  and  ex- 
perimentation. Not  least  among  the  problems  was  that  of  keeping  the 
weight  of  a  metal  car  within  reasonable  bounds,  without  sacrificing  its 
strength  and  serviceability,  light  weight  being  an  essential  requirement 
in  rapid  transit  operation. 


94  STEEL  PASSENGER  CAR  DESIGN 

As  the  best  practical  solution  of  the  car  question,  it  was,  therefore, 
decided  to  provide  wooden  cars  initially,  but  to  make  them  of  an 
advanced  type  with  metal  underframes,  protected  floors  and  copper- 
sheathed  sides,  and  to  mount  the  electric  apparatus  in  incombustible 
envelopes.  These  cars  were  rightly  considered  at  the  time  a  great 
advance  -upon  previous  practice  in  safeguarding  against  accidental 
fires.  The  first  lot  of  500  of  these  protected  wooden  type  subway  cars 
was  ordered  in  December  1902. 

While  it  was  necessary  to  insure  the  operation  of  the  subway  at 
the  date  set  for  its  opening  by  providing  the  initial  car  equipment, 
the  writer  believed  the  steel  car  feasible,  and  in  this  view  he  was 
encouraged  by  George  Westinghouse,  under  whose  stimulating  advice 
he  was  led  to  persevere  in  efforts  to  develop  a  metal  car  at  the  earliest 
possible  date.  A.  J.  Cassatt,  president  of  the  Pennsylvania  Eailroad, 
was  also  impressed  with  the  necessity  for  non-combustible  cars  in 
tunnel  service,  as  the  great  project  of  the  Pennsylvania  road  in 
building  a  tunnel  entrance  into  New  York  City  was  then  in  progress. 
He  accordingly  offered  to  the  subway  company  the  facilities  of  the 
Altoona  shops  to  build,  in  the  quickest  possible  time,  a  sample  steel 
car,  the  design  of  which  the  writer  had  completed  in  October  190>2. 
August  Belmont,  president  of  the  Rapid  Transit  Subway  Construction 
Company,  concurred  in  this  arrangement  and  early  in  1903  the 
Altoona  shops  started  upon  the  construction  of  this  car,  which  was 
completed  in  December  of  that  year.  Realizing  the  many  difficulties 
which  would  be  encountered  in  getting  material  promptly  at  that  time, 
commercial  shapes  were  quite  generally  used  in  the  design,  and  the 
car  as  built  was  found,  therefore,  to  be  quite  heavy  and  not  altogether 
sightly  in  appearance. 

The  company  still  needed  300  cars  to  complete  the  early  require- 
ments of  the  subway  operation  and  it  became  a  question  of  immediate 
necessity  to  determine  whether  these  cars  should  be  of  wood  or  be  of 
the  all-steel  construction.  The  writer  was  able,  from  experience  with 
the  sample  car,  to  develop  a  new  design  and  at  a  meeting  of  the 
executive  committee  of  the  subway  construction  company  early  in 
1904,  he  definitely  recommended  the  letting  of  contract  for  200  of 
the  new  design  of  steel  cars.  On  the  strong  endorsement  of  E.  P. 
Bryan,  general  manager  of  the  road,  Mr.  Belmont  decided  to  venture 
upon  this  important  innovation  in  railroad  operation.  The  contract 
for  the  200  steel  cars  was  accordingly  let  in  March  1904,  and  followed 
in  October  of  the  same  year  by  100  more.  Both  these  contracts  were 
taken  by  the  American  Car  &  Foundry  Company,  which  had  the 


DISCUSSION  95 

courage  of  its  convictions  in  assuming  the  heavy  responsibility  of 
turning  out  these  large  orders  at  specified  time  and  at  a  price  which 
was  not  out  of  line  with  that  of  the  previous  wooden  cars.  A  number 
of  these  cars  were  received  in  time  for  the  opening  of  the  subway, 
October  27,  1904,  and  are  running  today. 

During  the  same  year  the  writer,  who  also  had  charge  of  the 
electrification  of  the  Long  Island  Railroad,  placed  an  order  for  122 
steel  electric  motor  cars  of  practically  the  same  design  as  the  subway 
cars;  this  service  started  June  28,  1905.  The  Long  Island  was  the  first 
steam  railroad  in  the  country  to  adopt  steel  cars  for  its  passenger 
service. 

The  New  York  Central  a  year  later  placed  an  order  for  125  steel 
cars  and  inaugurated  their  electric  service  from  the  Grand  Central 
Station  in  January  1907. 

The  Pennsylvania  Railroad,  as  a  result  of  the  progressive  action 
of  Mr.  Cassatt,  endorsed  by  Samuel  Rea,  then  vice-president  of  the 
company,  adopted  steel  passenger  cars  for  all  trains  coming  into  the 
new  terminal,  a  decision  which  has  since  had  a  far-reaching  effect 
upon  the  standards  of  all  railways  of  the  country.  The  question  of 
the  best  design  for  through  passenger  train  cars  was  taken  up  ex- 
haustively and  systematically  by  this  company  and  was  made  the 
subject  of  a  report  by  a  special  committee  of  its  operating  officials  in 
May  1909.  Today  this  company  has  in  service  2139  steel  passenger 
cars,  excluding  a  large  number  of  sleeping  and  parlor  cars  of  the  Pull- 
man Company,  and  builds  no  other  type. 

WILLIAM  F.  KIESEL,  JK.  The  method  of  suspension  described  by 
Mr.  Summers  may  be  very  good  on  short  cars,  but  with  long  cars, 
especially  passenger  cars,  it  does  not  seem  sufficiently  flexible  in  the 
trucks  to  avoid  unbalancing  and  putting  the  cars  out  of  shape.  The 
bodies  are  long  and  the  cars  have  some  flexibility,  but  in  some  cases 
the  tracks  are  such  that  it  is  necessary  to  have  excessive  provisions  for 
flexibility  aside  from  that  in  the  truck. 

JOHN  A.  PILCITER.  Referring  to  Par.  2  of  Mr.  Summers'  paper, 
the  question  of  the  amount  of  wind  that  has  to  be  taken  up  between 
the  two  trucks  on  the  car  seems  to  be  exaggerated;  in  approaching  a 
curve  the  rise  in  elevation  of  the  outer  rail  is  about  1  in.  in  50  ft.  On 
the  ordinary  modern  passenger  car  truck  centers  are  about  50  ft.  apart 
so  that  the  total  amount  of  wind  is  about  1  in.  measured  at  the  rails. 
Considering  the  car  weighs  1.30,000  lb.,  with  trucks  approximately 


96  STEEL  PASSENGER  CAR  DESIGN 

20,000  Ib.  each,  and  the  car  body  about  90,000  lb.,  in  order  to  take 
care  of  the  wind  in  the  track,  the  springs  on  the  diagonals  of  the  car 
would  have  to  compress  %  in.  more  than  the  springs  on  the  opposite 
diagonal  assuming  the  springs  as  over  the  rails.  On  this  same  car 
this  would  mean  that  two  diagonals  would  have  20,150  lb.,  and  the 
opposite  two  24,850  lb.,  or  a  difference  of  4700  lb.  This  difference  in 
deflection  is  taken  from  actual  springs. 

To  analyze  this  in  connection  with  the  swinging  hangers,  assume 
these  hangers  to  be  11  in.  long,  and  to  be  located  at  an  angle  with  a 
vertical  of  .28  deg.  8  min.,  which  is  about  that  shown  in  the  cut,  and 
also  assume  that  they  are  located  approximately  over  the  track  (the 
movement  would  have  to  be  decreased  or  increased  in  proportion  to 
their  distance  from  the  rail  inside  or  outside)  with  a  load  of  22,500 
lb.  for  each  group  of  hangers. 

In  order  to  take  care  of  the  same  amount  of  wind  in  the  track  as 
considered  in  connection  with  the  springs,  that  is,  y%  in.  difference 
in  elevation  on  the  opposite  sides  of  the  track,  the  angle  would  be 
decreased  to  25  deg.  35  min.  on  one  side,  and  increased  to  approxi- 
mately 30  deg.  45  min.  on  the  opposite  side  in  order  to  bring  about 
stable  equilibrium.  The  vertical  loads  would  amount  to  24,935  lb. 
on  one  side,  and  20,065  lb.  on  the  opposite  side,  or  a  difference  of 
4870  lb.,  just  a  little  more  than  when  the  springs  were  used.  In 
calculating  the  deflection  of  the  springs  only  that  of  the  bolster 
springs  was  taken  into  consideration;  the  equalizer  springs  would  also 
have  to  take  an  additional  load,  and  would  help  to  reduce  the  differ- 
ence of  loads  necessary  to  bring  about  the  proper  amount  of  deflection. 

Looking  at  a  car  from  the  rear  approaching  a  curve,  when  the 
front  truck  enters  the  curve  the  centrifugal  force  at  that  point  would 
tend  to  throw  the  car  body,  relative  to  the  truck,  actually  in  the 
opposite  direction  from  what  it  should  move  in  order  to  equalize  the 
stresses.  This  would  put  additional  torque  in  the  body  of  the  car, 
which  would  not  be  present  in  the  case  when  springs  only  take  care 
of  this  movement.  The  torque  would  be  rather  reduced  at  the  time  of 
entering  the  curve  when  the  springs  only  are  used. 

When  both  trucks  are  on  the  curve  all  of  the  wind  is  out  of  the 
car ;  the  centrifugal  force  in  that  case  throws  the  car  body  toward  the 
outside,  and  would  tend  to  augment  the  lift  in  the  track  on  the  out- 
side, which  is  hardly  desirable. 

Angular  hangers,  while  they  may  not  have  been  intended  for  the 
purpose  described,  have  been  in  use  for  a  number  of  years.  It  is  very 
questionable  whether  they  are  of  any  advantage. 


SYMPOSIUM  ON  FIRE  PROTECTION 

No.  1393  a 

DEBARMENT  OF  CITY  CONFLAGRATIONS 

BY  ALBERT  BLAUVELT,  CHICAGO,  ILL. 
Member  of  the  Society 

Opinions  take  opposite  sides  as  to  whether  the  central  districts 
of  our  leading  cities  are  today  subject  to  conflagration. 

2  Passing  over  interested  and  private  opinions,  the  1911  report 
of  the  Joint  Committee  of  the  Senate  and  Assembly  of  the  State  of 
New  York,  on  insurance  and  fire  waste;  the  Illinois  Fire  Insurance 
Commission  Keport  of  1911;  the  Ohio  Fire  Marshal  Eeport  for  1907; 
the  United  States  Department  of  the  Interior,  Bulletin  418,  of  1910; 
the  Wisconsin  Senate  and  Assembly  Committee  of  1913  and  all  other 
public  reports  the  writer  can  find  agree  that  each  of  our  cities  is  today 
subject  to  conflagration.     Our  cities  appear  to  spend  in  public  and 
private  ways  enough  money  to  make  a  conflagration  impossible  for  the 
central  districts,  but  they  do  not  achieve  this  result. 

3  The  horizontal  hot  blast  of  a  heavy  fire  driven  by  wind  ranges 
from  a  few  hundred  to  more  than  a  thousand  feet,  whereas  the  most 
powerful  hose  streams  are  not  effective  at  over  one  hundred  to  two 
hundred  feet. 

4  Such  fires  develop  in  the  heart  of  our  cities  in  the  face  of 
more    firemen    and    apparatus    than    can    be    quickly    used,    as    at 
Boston  in  1872  and  1889 ;  Montreal  in  1901;  Paterson  in  190&;  Balti- 
more and  Toronto  in  1904;  and  such  fires  also  develop  in  city  out- 
skirts or  cheap  quarters  and  by  force  of  wind  sweep  into  the  city 
proper  as  at  Portland,  Me.,  in  1866 ;  Chicago  in  1871; , St.  John,  N.  B., 
in  1877;  Ottawa-Hull  in  1900;  Jacksonville,  Florida,  in  1901;  at 
Chelsea,  Mass.,  and  other  cities. 

5  Inasmuch  as  any  engineering  plan  to  debar  conflagration,  if 
intended  to  cover  an  entire  city,  inclusive  of  cheap  districts,  would 
be  prohibitive  in  cost;  any  such  plan  must  be  limited  to  the  central 
or  high  value  district  and  designed  to  prevent  free  spread  of  fire 

Presented    at   the    Spring    Meeting,    Baltimore    1913,    of    THE    AMERICAN 
SOCIETY  OF  MECHANICAL  ENGINEERS. 

171 


172  DEBARMENT  OF  CITY  CONFLAGRATIONS 

within  same,  and  also  debar  any  deep  inroad  of  conflagration  from 
without  such  district. 

6  Every  conflagration  must  necessarily  begin  in  one  of  two  ways, 
or  a  combination  of  both,  Chicago  in  1871  and  Baltimore  in  1904 
being  examples  of  the  two  types. 

7  The  Chicago  fire  started  outside  of  the  congested  district, 
developed  into  hot-blast  form,  and  swept  through  and  beyond  the 
congested  district,  and  burned  out  for  lack  of  fuel. 

8  On  the  other  hand,  the  Baltimore  fire  began  in  the  heart  of 
the  city  and  ramified  more  swiftly  than  the  firemen  could  operate; 
then  took  the  hot  blast  form  and  burned  out  for  lack  of  fuel. 

9  Such  a  hot  blast  has  never  been  stopped  by  firemen  while  the 
wind  held,  but  has,  however,  been  checked  and  deflected  upward  by 
barriers  consisting  of  two  or  more  fire  walls  or  their  equivalent, 
with  a  free  air  space  between,  as  per  the  known  instances  of  fires  out 
of  control,  which  have  been  stopped  by  a  mere  alley  if  fully  shuttered 
on  each  side. 

10  It  has  also  been  possible  to  absorb  the  hot-blast  attack  of 
such  fires  by  a  very  deep  and  fixed  mass  of  spray  in  the  form  of 
sprinkler ed  buildings.     The  Boston  fire  of  1893  was  largely  absorbed 
by  an  exceptionally  good  water  supply  in  such  form,  and  somewhat 
similar  experiences  have  been  had   at  Toronto  in   1904,  and  other 
cases. 

11  These  successful  experiences  in  checking  hot-blast  fires  by 
deflecting  the  flame  or  by  absorbing  it  in  a  mass  of  spray  have  been 
but  little  appreciated  and  instead  of  acting  upon  the  lessons  which 
they  teach,  our  cities  today  have  a  collection  of  safeguards,  part  of 
which  lend  themselves  to  the  debarment  of  conflagrations  and  part  of 
which  do  not. 

SAFEGUARDS  WHICH  SINGLY  CANNOT  DEBAR  CONFLAGRATIONS 

12  The  recognized  and  partly  recognized  safeguards  against  fire, 
no   one    of    which    alone    can    debar    conflagrations,    are    twelve    in 
number,  viz.,  fire  prevention;  the  fire  limits;  the  water  supply;  the 
fire  department;   the  high-pressure  fire   system;   the   uniform  hose 
thread;  the  water  curtain;  the  so-called  fireproof  building;  the  hori- 
zontally  divided   building;   the   protected   window;   the   sprinklered 
building;  and  the  piped  building. 

13  Dynamite,  private  hose,  steam  jets,  carbonic  gas  systems,  and 
fire  walls  separate  from  buildings  are  not  listed  because  they  are  not 
recognized  by  fire  chiefs  for  valid  reasons. 


ALBERT  BLAUVELT  173 

14  Fire    Prevention.     The    preponderance    of    disasters    from 
trivial,  unknown  or  unguessable  causes  appears  to  forbid  hope  of 
elimination  of  conflagrations  through  fire  prevention.    A  half  century 
of  experience  also  shows  that  the  skill  and  effort  directed  to  prevent 
city  fires  from  becoming  disasters  has  been  successful  within  0.00003 
of  the  total  fires.    This  0.00003  is  what  has  hurt,  and  appears  to  be 
the  only  considerable  task  of  correction  remaining  for  the  engineer. 

15  The  Fire  Limits.    This  is  an  expression  indicating  a  central 
territory,    within    which    frame    construction    or    shingle    roofs    are 
prohibited    and    better    construction    enforced,    especially    for    large 
area  buildings.     The  elimination  of  frame  buildings  and  shingles  is 
an  essential  part  of  any  plan  to  debar  conflagration. 

16  The  Water  Supply.     The  water  supply  is  indispensable  and 
also  adequate  in  most  of  our  cities.    Were  this  not  so,  Baltimore  and 
other  conflagrations  would  have  gone  to  the  extent  of  San  Francisco, 
whose  water  mains  were  wrecked  by  earthquake. 

17  The  Fire  Department.     While  no  fire  department  has  ever 
been  able  to  put  water  on  the  front  or  rear  of  any  hot-blast  type  of 
conflagration,  nevertheless,  the  fire  departments  at  time  of  conflagra- 
tion have  been  of  gigantic  value  in  keeping  the  fire  from  spreading 
across  the  wind,  in  extinguishing  brands  thrown  far  ahead,  etc.    The 
fire  department,  therefore,  is  indispensable  and  this  paper  argues  to 
increase  its  opportunity,  but  not  its  cost  and  size. 

18  The  High-Pressure  System.    Those  cities  which  are  partly 
equipped  with  costly  high-pressure  systems  enjoy  an  advertisement 
which  does  not  appear  to  be  shared  nor  courted  ,by  the  group  of  valley 
cities  with  reservoirs  on  high  bluffs  or  hills.    The  latter  afford  a  high- 
pressure  service  for  the  whole,  not  parts  of  such  cities.     Powerful 
high-pressure  hydrant  systems  have   also  long  existed  in   a  goodly 
number  of  cities  in  the  form  of  special  inland  hydrant  lines  operated 
by  fire  boats. 

19  High-pressure   develops   long   and   large   hose   streams,   but 
there  is  nothing  about  it  to  enable  firemen  to  use  such  hose  streams 
either  in  advance,  or  in  the  rear  of,  a  hot-blast  conflagration,  nor  is 
a  high-pressure  system  especially  flexible  to  check  the  ramification  of 
fire  as  at  Baltimore  in  1904. 

20  The  Uniform  Hose  Thread.     Since  the  fire  department  is 
indispensable,  ability  to  double  up  departments  is  obviously  wise  and 
Mr.  Griswold's  long  labors  and  the  report  of  the  sub-committee  on 
fire  protection  on  this  subject  are  exactly  in  point. 

21  The  Water  Curtain.     It  is  fair  to  say  that  a  water  curtain 


174  DEBARMENT  OF  CITY  CONFLAGRATIONS 

has  successfully  held  off  some  heavy  fires,  but  never  a  conflagration. 
The  fatal  weakness  of  the  water  curtain  is  that  it  is  blown  away  or 
scattered  by  the  brisk  breeze  which  necessarily  accompanies  a  hot- 
blast  conflagration.  The  depth  of  the  spray  is  also  far  too  shallow. 

2<2  The  water  curtain,  as  shown  by  fire  record  results,  is  a 
valuable  safeguard  for  moderate  exposure  fires,  or  even  for  fairly 
severe  exposure  when  favored  by  quiet  air,  but  fails  in  severe  tests. 

23  The  Fireproof  Building.     The  typical,  so-called  "fireproof" 
building,  having  merely  incombustible  floors,  roof  and  walls,  cannot 
debar  a  conflagration  (because  of  its  unprotected  windows  and  large 
volume  of  contents)  any  more  than  can  an  ordinary  brick  building 
with  a  good  roof. 

24  A  hot-blast  conflagration  moves  laterally,  and  a  "fireproof" 
building  in  its  path,  as  evidenced  at  Baltimore,  is  merely  a  crate  which 
holds  up  the  fuel  contents  in  position  for  free  burning  and  augments 
the  general  hot  blast. 

25  It  is  contents,  not  buildings,  which  make  the  bulk  of  property 
loss ;  contents,  not  buildings,  which  are  hazardous ;  and  contents  cause 
buildings  to  burn  in  most  cases. 

26  Eepeated  experience  shows  that  no  building  can  withstand 
the  heat  due  to  burning  any  large  quantity  of  contents  or  even  very 
moderate  contents  if  in  a  large  rotunda,  half  floor  office  or  like  large 
area.     The  writer  submits  to  all  who  are  authorities  on  heat  the 
feasibility  of  constructing  a  high   structure  of  large  retorts,  each 
capable  of  restraining  10,000  to  50,000  Ib.  of  ignited  fuel,  and  also 
filling  with  customary  taste  and  beauty  the  needs  of  utility  and  health 
for  habitation. 

27  The  fireproof  building  has  unequalled  habitability  and  utility 
and  also  lends  itself  admirably  to  conversion  into  a  piped  building, 
and  even  more  excellently  lends  itself  to  conversion  into  a  building 
having  protected  windows. 

28  The  Horizontally  Divided  Building  is  designed  to  hold  a  fire 
from  rising  through  the  floors.   Repeated  experience  in  tall  buildings 
has  proven  that  excessively  large  and  dangerous  fires  develop  quickly 
if  the  floors  are  not  fire  tight. 

29  .Such  horizontal  division  is  obviously  of  no  value  against  a 
hot-blast  fire  moving  laterally  from  without,  and  it  also  does  not  pre- 
vent an  internal  fire  from  jumping  from  floor  to  floor  on  the  outside 
of  the  building. 

30  Horizontal  fire-tight  construction  is  very  rarely  found  when 


ALBERT  BLAUVELT  175 

fire-tested,  its  worst  drawback  being  that  in  the  opinion  of  the  public 
it  injures  the  habitability  and  utility  of  the  building,  hence  all  sorts 
of  concessions  are  made. 

31  The  Protected  Window.     Protected  windows  can  debar  city 
conflagrations,  but  do  not  because  there  are  too  few  of  them,  except  in 
a  few  special  and  minor  localities. 

32  The  Piped  Building.     The  building  piped  with  fusible  out- 
lets, whether  with  automatic  water  supply  or  with  water  promptly 
applied,  can  but  does  not  debar  city  conflagrations  for  the  same  rea- 
son given  respecting  the  protected  window. 

TEUE  HOT-BLAST  CONFLAGRATIONS  CAN  BE  DEFLECTED  OR  ABSORBED 

33  Hot-blast  conflagrations  have  been  successfully  controlled  both 
by  deflection  and  absorption. 

34  Taking  up  the  deflection  idea  first,  all  will  doubtless  agree 
that  if  the  four  walls  of  every  city  building  were  solid  brick  with  no 
doors  or  windows,  a  spread  of  fire  would  be  impossible,  even  with  no 
fire  department.     From  this  it  follows  that  if  all  doors  and  windows 
were  protected  by  wire  glass,  shutters  or  fire  curtains,  the  walls  of 
the   buildings    would,    have   the    same   tendency.      Any    experienced 
fire  chief  will  testify  to  the  enormous  fire-stopping  effect  of  an  alley 
shuttered  on  both  sides,  the  heat  and  hot  blast  being  deflected  up- 
ward. 

35  Experience  shows,  however,  that  when  a  hot  blast  reaches  a 
building  prepared  to  act  as  a  deflector  by  suitable  protection  for  its 
doors  and  windows,  the  first  result  is  partial  failure.     This  is  owing 
to  the  fact  that  the  heat  will  radiate  through  the  wired  glass,  or  leak 
through  the  shutters,  and  ignite  the  contents. 

3>6  Nevertheless,  there  will  be  a  retardant  effect  and  it  is  obvious 
that  if  other  buildings  located  to  the  right  or  left  of  the  center  of  the 
hot  blast  have  window  openings,  similarly  stopped,  they  must  suffer 
less  and  the  elsewise  lateral  ramification  of  the  fire  decrease. 

37  The  hot  blast  is  thus  largely  deflected  upward,  partly  checked 
and  less  able  to  cross  the  next  street  or  alley,  assuming  protected  win- 
dows throughout. 

38  Just  how  many  deflector  walls  and. air  spaces  could  be  jumped 
or  burned  through  by  a  conflagration  of  given  severity  is  a  matter  of 
judgment  based  on  observation,  precisely  as  the  extinguishing  power 
of  a  hose  stream  is  a  matter  of  judgment  from  experience,  not  reduci- 
ble to  exact  figures. 

39  The  writer  submits  that  if  all  the  alley  windows  were  pro- 


176  DEBARMENT  OF  CITY  CONFLAGRATIONS 

tected  and  also  all  the  street  windows  on  the  second  floors  and  above 
in  the  solid  three  and  four-story  parts  of  a  town,  a  conflagration  from 
without  could  not  then  bore  a  hole  or  a  bay  into  such  a  district  deeper 
than  through  four  deflector  walls  and  across  three  air  spaces,  which 
would  mean  two  blocks  and  three  streets,  of  which  one  might  be  an 
alley. 

40  .Nfot  that  the  fire  would  be  put  out,  nor  that  tongues  and 
fire  brands  would  not  have  to  be  taken  care  of;  but  that  the  hot  blast 
would  be  deflected  upward  so  the  firemen  could  take  a  front  stand 
and  the  general  advance  and  ramification  of  the  fire  subside  to  a  state 
of  normal  fire  department  control. 

DEBARMENT  OF  CONFLAGRATIONS  BY  ABSORPTION 

41  There  remains  but  one  other  known  means  to  regain  con- 
trol of  a  conflagration,  that  of  absorbing  the  hot  blast  by  means  of 
the  piped  building.     Experience  has  demonstrated  that  a  hot  blast 
can  be  absorbed  by  a  spray  if  the  spray  be  very  deep  and  fairly  housed 
from  the  wind  as  is  true  of  the  cage  of  spray  represented  by  a  sprinkler 
installation  in  full  action  in  a  building  whose  windows  have  burned 
out. 

42  The  most  notable  demonstration  of  this  was  the  Brown-Durell 
sprinklered  building  at  Boston  in  1893.     Inasmuch  as  this  building 
became  a  single  large  cage  of  spray  which  absorbed  the  main  body 
of  a  down-town  fire  that  was  wholly  beyond  control,  it  is  certain  that 
a  row  of  such  cages  of  spray,  if  placed  two  or  more  deep,  would  always 
accomplish  the  same  thing,  and  do  so  without  the  aid  of  protected 
windows. 

43  The  writer  submits  that  if  a  city  throughout  all  of  its  three 
and  four-story  and  higher  parts  were  composed  exclusively  of  suitably 
piped  buildings,  and  special  water  supply  provided,  a  conflagration 
from  a  district  without  could  not  burn  across  a  street,  through  a 
block  deep  of  spray,  and  across  the  next  street. 

44  The  fire  would  not  be  put  out  and  fire  brands  would  have 
to  be  taken  care  of;  but  there  would  be  no  ramification  of  fire  in  the 
sprinklered  territory  and  there  would  be  a  full  restoration  of  normal 
fire  department  control. 

VALUES,  COSTS,  GAINS 

45  The  Boston  big  fires  proved  out  burnable  property  values  at 
a  rate  of  over  $500,000,000  per  square  mile,  and  it  is  well  known  that 


ALBERT  BLAUVELT 


177 


today  there  are  several  city  centers  which  have  grown  to  a  far  higher 
rate  of  concentration  of  value. 

46  It  seems  fair  to  assume  $260,000,000  per  square  mile  as  an 
average  burnable  value  over  the  central  districts  of  our  twenty  leading 
cities. 

47  For  such  a  square  mile,  standard  automatic  sprinklers   (in- 
cluding masonry)   would  cost  about  four  per  cent  of  the  burnable 
values,  or  $10,000,000  with  fixed  charges  of  about  16  per  cent  per 
year.  - 

48  Empty  sprinklers,  or,   protected  windows,   would  each  cost 

TABLE   1     FIXED  CHARGES,  FIRE  COST  SAVING  AND  NET  GAIN  ON  A  BASIS  OF 
$250,000,000  PER  SQUARE  MILE 


FOR  STANDARD 

FOR  EMPTY 

FOR  SHUTTERS, 

AUTOMATIC 

SPRINKLERS  AND 

FIRE  CURTAINS, 

ON  AN  ANNUAL  BASIS 

SPRINKLERS  WITH 

PIPING  TO  BE 

OR  WIRED  GLASS 

DOUBLE  WATER 

SUPPLIED  BY  THE 

APPLIED  AS  PER 

SUPPLY 

FIRE  DEPARTMENT 

PRECEDING  TEST 

Investment  per  sq.  mi                .  .  . 

$10,000,000 

$5,000,000 

$5,000,000 

Fixed  charges  as  given  above  

1,600,000 

450,000 

450,000 

Saved  by  eliminating  risk  of  con- 

flagration at  33  ct.  per  $100.  .  .  . 

825,000 

825,000 

825,000 

Saved  by  eliminating  common  ex- 

posure fires  at  7  ct.  per  $100.  .  .  . 

175,000 

175,000 

175,000 

Saved  by  reducing  fire  cost  within 

buildings  in  which  fire  originated. 

2,000,000 

1,125,000 

nominal 

Difference    between    charges    and 

savings 

1,400,000 

1,675,000 

550,000 

Per  cent  earned  by  savings  

14 

33.5 

11 

about  half  as  much,  or  $5,000,000  per  square  mile  for  either,  and  each 
incur  fixed  charges  (about  the  same  as  the  buildings),  or  about  9  per 
cent. 

49  The  savings  per  $100  of  burnable  values  per  year,  would  be 
as  given  in  Table  1. 

50  In  surveying  any  actual  square  mile  it  would  develop  that 
but  one  of  the  three,  viz.,  protected  windows,   automatic  pipes,  or 
empty  sprinkler  pipes,  would  best  suit  any  one  building,  and  this 
would  be  likely  to  result  in  a  detail  plan  calling  for  gross  investment 
of  about  three  per  cent  of  the  burnable  values  at  a  net  gain  of  about  18 
per  cent. 

51  But  figures  cannot  include  the  grief,  loss  of  work  and  trade 
following  every  large  conflagration. 


178  DEBARMENT  OF  CITY  CONFLAGRATIONS 

52  Our  fire  limits,  fire  departments  and  waterworks  are  today 
well  developed,  and  protected  windows  or  piped  buildings  throughout 
the  costlier  districts  are  all  that  is  needed,  to  debar  conflagrations. 

RECAPITULATION 

53  To  recapitulate  the  advantages  and  disadvantages  of  the  pro- 
tected window  and  the  two  types  of  piped  buildings : 

54  The  protected  window  delays  the  entry  of  severe  fires  and  also 
prevents  general  ramification  of  fire  through  innumerable  window 
openings. 

55  Not  that  the  protected  window  does  this  perfectly,  because 
shutters  may  be  out  of  order  or  not  within  reach  to  close  if  open,  and 
because  wired  glass  transmits  heat  by  radiation  very  rapidly.     Never- 
theless, as  aided  by  existing  air  spaces,  alleys  and  streets,  the  pro- 
tected window  is  a  proven  success. 

56  The  protected  window  is  beginning  to  be  required  in  building 
codes ;  it  also  is  tangible  to  the  public  eye,  something  that  can  be  seen 
as  representing  a  fire  stop  or  check;  in  wired  glass  form  it  has  some 
working  advantages,  at  least  for  skylights,  and  finds  favor  with  archi- 
tects on  the  better  class  of  buildings;  in  the  form  of  shutters,  the 
fire-stop  effect  is  better  than  for  wired  glass,  but  this  is  largely  offset 
by  the  fact  that  shutters  do  not  get  the  care  which  comes  to  a  window 
which  is  in  more  or  less  constant  use. 

57  The  advantage  of  the  piped  building  with  automatic  double- 
source  water  supply,  the  well  known  sprinklered  building,  is  first  of 
all  the  protection  to  life.     Apparently  this  specific  form  of  fire  protec- 
tion is  the  only  one  which  to  any  dependable  degree  conserves  life. 
An  experience  with  say  10,000  buildings  over  a  period  of  about  15 
years  gives  rise  to  the  statement  that  no  life  has  ever  been  lost  in  a 
building  so  equipped,  either  by  fire  or  smoke,  and 'to  the  best  of  the 
writer's  knowledge  this  is  literally  true. 

58  The  operation  of  an  automatic  sprinkler  system  develops  a 
powerful  drenching  spray  not  only  on  the  fire  but  around  it,  and 
compels  escaping  smoke  to  pass  through  a  dense  spray  which  takes 
up  the  acrid  quality  and  heavier  carbon  contents  of  the  smoke,  and 
thus  has  much  to  do  with  the  protection  to  life. 

59  While  mathematical  safety  against  loss  of  life  is  probably 
impossible,  it  is  within  the  truth  to  say  that  where  people  are  in 
masses,  or  are  asleep,  safety  cannot  exist  if  the  fire  hazards  are  not 
under  the  automatic  sprinkler. 


ALBERT  BLAUVELT  179 

60  A  second  advantage  of  the  automatic  sprinkler  system,  and 
the  one  most  in  point  under  the  title  of  this  paper,  is  that  it  has  been 
found  in  practice  that,  given  brick  buildings,  well  secured  pipes,  and 
reasonable  water  supply,  a  fire  even  when  of  conflagration  magni- 
tude cannot  burn  completely  through  such  spray  further  than  the 
depth  of  one,  or  say  two,  buildings. 

61  A  third  advantage  is  that  the  fires  are  put  out  so  quickly 
and  with  such  economy  of  water  by  reason  of  its  accurate  application, 
with  so  little  smoke  and  so  great  a  reduction  of  the  harmful  quality 
of  the  smoke  that  the  aggregate  fire,  water,  and  smoke  damage  to 
goods  is  far  less  than  for  any  other  form  of  protection. 

62  Referring  to  the  plain  piped  building,  or  building  equipped 
with  fusible  sprinklers  on  empty  piping  with  exterior  hose  coupling 
for  fire  department  use  and  relying  solely  on  the  fire  department  for 
water  supply,  the  main  advantage  is  that  the  first  cost  and  low  fixed 
charges  make  it  applicable  to  the  medium  value  buildings. 

63  Another  advantage  is  that  of  safety  to  life,  compared  with 
that  of  buildings  not  piped  at  all,  because  in  practice  the  empty 
sprinklers  can  be  operated  nearly  as  quickly,  and  necessarily  to  the 
same  effect  as  automatic  water-supplied  sprinklers. 

64  Still  another  advantage  is  that  the  technique  and  upkeep  es- 
sential to  efficiency  are  far  less  than  with  the  full  standard  automatic 
sprinkler  equipment. 

65  The  main  disadvantage  of  the  protected  window  is  that  it 
protects  only  as  between  neighboring  buildings  and  this  saving  aver- 
ages too  small  an  amount  to  cover  its  fixed  charges,  on  a  basis  of 
every-day  fires. 

66  A  disadvantage  of  the  standard  automatic  sprinkler  system 
is  that  it  is  a  special  engineering  product,  technical  to  a  high  degree, 
yet  depending  on  this  quality  for  its  efficiency,  an  efficiency  imparted 
by  a  few  skilled  contractors  and  experts.     The  system  therefore  is 
open  to  criticism  by  all  who  rail  at  any  control  of  skill  or  service. 

67  Another  objection  to  this  form  of  piped  building  is  that  its 
water  supplies  are  often  direct  from  city  mains  through  the  influence 
of  large  property  owners,  thereby  saving  them  the  expense  of  private 
water  supply.     In  Manhattan  Island  and  Chicago  the  city  water  is. 
of  too  low  a  pressure  to  be  so  used,  but  in  other  cities  there  are  too 
few  sprinklered  buildings  to  check  a  conflagration  and  just  about 
enough  of  them  to  jeopardize  complete  crippling  of  waterworks  and 
fire  department  at  such  a  time  by  reason  of  these  buildings  being 


180  DEBARMENT  OF  CITY  CONFLAGRATIONS 

wrecked  and  bleeding  the  general  water  supply  throughout  the  break- 
ing of  large  pipes. 

68  Hence  a  wise  requirement  for  a  piped  district,  would  be  to 
provide  a  special  border  pipe  line  into  which  water  would  be  pumped 
or  admitted  under  control. 

69  ©till  another  disadvantage  of  standard  automatic  sprinkler 
equipment  is  in  first  cost  and  in  fixed  charges.     The  investment  and 
fixed  charges  do  not  have  any  fairly  constant  relation  to  the  value  of 
building  plus  contents,  and  at  city  labor  costs  are  usually  excessive, 
except  for  large  and  costly  buildings. 

70  A  disadvantage  of  the  empty  pipe  sprinkler  system  is  that 
this  mode  of  protection  has  as  yet  but  few  applications;  no  extended 
study  has  been  given  the  art  of  cheap  extinguishment  of  fire  in  me- 
dium value  property.     Another  disadvantage  is  that  fire  department 
practice  is  at  variance;  some  chiefs  favor  and  ask  for  such  equip- 
ment, and  others  evade  or  object. 

71  It  does  not  seem  to  be  generally  realized  that  a  building  in 
a  central  district  does  not  burn  badly  before  the  department  arrives. 
Were  this  not  so,  modern  fire  departments  would  not,  as  the  records 
show  year  after  year,  hold  the  fires  within  moderate  loss,  except  0.003 
to  0.005  of  the  total.     The  fire  department  does  arrive  while  the  fires 
are  yet  incipient,  though  perhaps  inaccessible.     It  seems  to  be  accepted 
as  a  matter  of  course  that  a  costly  proportion  of  buildings  shall  burn 
and  soak,  subsequent  to  the  arrival  of  the  department,  for  the  sole 
reason  that  the  department  cannot  quickly  put  ample  water  where, 
and  only  where,  it  is  needed.     Yet  to  do  the  latter  is  all  that  the  stand- 
ard automatic  sprinkler  equipment  does  or  professes  to  do,  and  water 
can  be  supplied  to  empty  pipes  nearly  as  quickly  by  firemen  as  by  a 
private  tank. 

72  Even  in  a  case  of  purposely  delayed  alarm  and  sprinklers 
shut  off  (incendiary),  the  writer  has  seen  work  done  in  this  manner 
by  only  one  steamer  with  wonderful  success,  extinguishing  a  four- 
story  fire  which  otherwise  would  have  required  many  hose  streams, 
and  this  after  there  was  no  time  to  set  up  ladders  and  place  hose. 

73  The  fire  cost  of  empty  sprinkler  equipment  would  admitttedly 
be  greater  than  for  automatic  sprinkler  equipment  because  while  there 
would  be  no  failures  through  pipes  frozen  or  valves  shut  off,  the  fire 
department  would  not  put  water  on  the  fires  at  quite  as  early  a  stage 
of  incipiency. 

74  A  willing  fire  department,  however,  would  put  water  on  the 


ALBERT  BLAUVELT  181 

fire  through  such  pipes  while  a  fire  was  yet  incipient,  because  our  fire 
department  records  show  that  the  department  arrives  and  the  vast 
majority  of  city  fires  are  put  out  while  incipient. 

75  To  pay  for  the  greater  fire  and  water  damage  in  practice 
with  empty  pipes  as  compared  with  automatic  sprinkler  equipment, 
the  figures  given  in  Table  1  allow  for  the  typical  square  mile,  $825,000 
per  year,  to  say  nothing  of  $1,160,000  reduction  of  annual  fixed 
charges. 

76  However,  the  standard  automatic  sprinkler  system  has  been 
fully  demonstrated  for  over  20  years,  yet  it  is  but  just  coming  into 
its  own,  and  the  empty  sprinkler  system  must  in  turn  wait  for  recog- 
nition and  extend  in  application  by  degrees. 

77  The  practical   difficulty,  therefore,   of   debarring   disastrous 
conflagrations  in  our  cities  seems  not  in  lack  of  means,  nor  in  lack 
of  knowledge  based  on  experience,  so  much  as  in  the  lack  of  agree- 
ment on  a  plan,  and  the  difficulty  of  apportionment  of  expense. 


No.  1393  & 

BALTIMORE  HIGH-PRESSURE  FIRE 
SERVICE 

BY  JAMES  B.  SCOTT,  BALTIMORE,  MD. 
Member  of  the  Society 

The  Conflagration  of  1904.  The  conflagration  of  1904  was  due  to 
the  simultaneous  occurrence  of  an  incipient  warehouse  fire  gaining 
headway  unobserved  on  a  ,Sunday  morning;  a  high  wind;  inferior 
building  construction  and  inadequate  fire-fighting  equipment. 

2  During  the  first  eight  hours  of  the  fire  the  wind  was  blowing 
from  the  southwest,  after  which  it  shifted  90  deg.  to  the  northwest, 
causing  the  fire  to  advance  with  its  broadside  of  1500  ft.  for  a  front. 
Although  supplemented  by  engines  from  other  cities,  after  the  fire 
had  got  beyond  control  the  operations  of  the  department  might  be 
described  as  a  skilful  retreat,  an  engine  and  a  truck  being  lost  under 
falling  walls  because  the  retreat  had  not  been  sufficiently   rapid. 
Dynamite  was  freely  used  by  skilful  operators,  but  was  practically 
ineffective.     The  fire  raged  for  30  hours,  covering  150  acres,  causing 
a  loss  of  $100,000,000  and  finally  burned  itself  out  when  the  wind 
changed  again  to  the  north  and  drove  the  flames  toward  the  open 
harbor. 

3  There  was  no  scarcity  of  the  water  supply.     The  topography 
of  Baltimore  shows  elevations  ranging  from  6  to  460  ft.  above  mean 
low  tide,  and  to  prevent  excessive  pressures  in  the  low  lying  sections 
or  a  deficiency  in  those  higher  up,  the  supply  is  divided  into  five 
separate  services.     The  "low"  and  "middle"  services  are  fed  entirely 
by  gravity,  the  three  higher  services  being  supplied  by  pumps  and 
high  storage  reservoirs.     Suitable  by-passes  are  provided  so  that  in 
an  emergency  any  service  can  be  supplied  from  the  next  higher.     At 
the  time  of  the  conflagration  there  was  available  a  total  reservoir 
capacity  of  over  1,750,000,000  gal.,  in  addition  to  pumps  of  63,000,- 
000  gal.  capacity.     At  that  time  the  consumption  for  domestic  and 
industrial  purposes  was  about  60,000,000  gal.  daily,  and  the  draft 
from  the  reservoirs  for  fighting  the  conflagration  was  approximately 
the  same  amount,  or  a  trifle  over  3  per  cent  of  the  available  reservoir 

Presented   at   the    Spring   Meeting,    Baltimore    1913,    of    THE    AMERICAN 
SOCIETY  OF  MECHANICAL  ENGINEERS. 

183 


184 


BALTIMORE  HIGH-PRESSURE  FIRE  SERVICE 


JAMES  B.  SCOTT  185 

capacity.  In  addition  to  the  reservoir  draft,  about  two  hours  after 
the  fire  started  the  two  17,500,000-gal.  pumps  in  one  of  the  high- 
service  pumping  stations  were  by-passed  into  the  "middle"  or  upper 
gravity  service.  The  fire  originated  in  the  middle  service  district 
and  shortly  afterward  extended  into  the  low  service  district.  As 
soon  as  this  occurred  the  by-pass  between  the  two  was  opened,  and 
the  pressure  was  maintained  at  80  Ib.  during  the  remainder  of  the 
fire. 

4  The  operations  against  the  conflagration  demonstrated  that, 
for  effective  fighting  of   a   dangerous  fire,   large  volumes  of  water 
must  be  delivered  on  the  fire  with  the  least  possible  delay,  and  at 
suitable   pressures.     To   meet   these   requirements   a   separate   high- 
pressure  fire  service  was  designed  and  installed,  covering  the  greater 
portion  of  the  congested  value  districts  of  the  city. 

5  Characteristics  of  the  Congested  Value  Districts.  The  corporate 
limits  of  Baltimore  embrace  an  area  of  31%  sq.  mi.,  with  a  density  of 
population  of  17,729  per  sq.  mi.,  a  density  greater  than  any  other  of 
the  larger  American  cities.     The  congested  value  districts  cover  ap- 
proximately  300   acres,   the   area   at   present   covered   by   the   high- 
pressure  mains  is  about  175  acres,  or  assuming  that  the  territory  for 
200  ft.  outside  the  mains  is  protected,  the  high-pressure  district  may 
be  considered  to  be  245  acres. 

6  The  elevations  of  the  congested  value  districts  vary  from  6  ft. 
to  100  ft.  above  mean  low  tide,  about  one  half  of  the  area  being 
below  elevation  50.     The  pump  centers  at  the  high-pressure  station 
are  at  about  elevation  12.5. 

7  The  character  of  the  building  construction  in  the  congested 
value  districts  varies  from  first-class  modern  fireproof  structures  to 
converted  residences,  except  in  the  rebuilt  burned  district,  where  a 
better  type  of  construction  exists.     In  the  districts  in  question  all 
electric  wires  have  been  placed  underground  in  conduits  owned  by 
the  city,  with  the  exception  of  the  street  railway  trolleys.     Before  re- 
building the  burned  district,   several  narrow  and  congested  streets 
were  widened  and  plazas  established  around  important  public  build- 
ings, so  that  the  conflagration  hazard  in  that  section  has  been  con- 
siderably decreased. 

DESIGN  OF  THE  HIGH-PRESSURE  SYSTEM 

8  The  Time  Element.     High-speed  automobile  hose  wagons  are 
provided,  housed  at  convenient  locations,  in  order  that  the  minimum 


186  BALTIMORE  HIGH-PRESSUKE  FIRE  SERVICE 

time  possible  may  be  consumed  in  reaching  the  scene  of  a  fire  after 
the  alarm  is  received.  Each  wagon  is  equipped  with  a  four-cylinder 
four-cycle  motor  of  sufficient  power  to  develop  a  speed  of  30  mi.  an 
hr.  through  the  streets  of  the  city,  with  a  load  of  5000  Ib.  Each 
body  is  50  in.  by  34  in.  by  12  ft.  inside,  and  carries  2000  ft.  of  3-in. 
hose.  Each  body  is  equipped  with  one  2000-gal.  Morse  Invincible 
monitor  nozzle  and  two  1100-gal.  monitors. 

9  The  Pressure  Element.     The  pressure  required  for  effective 
work  varies  widely  according  as  conditions  demand  the  flooding  out 
of  a  basement  fire  or  fighting  on  the  top  floor  of  a  modern  skyscraper. 
At  times  both  extremes  may  be  required  simultaneously. 

10  To  meet  efficiently  these  conditions  requires  the  maximum 
pressure  to  be  available  at  each  hydrant,  with  means  for  the  separate 
control  of  the  pressure  on  each  hose  line.     The  specifications  called 
for  a  combination  operating  valve  and  regulator  capable  of  adjust- 
ment from  shut-off  to  50,  75,  100,  125,  or  150  Ib.,  or  if  desired,  to 
the  full  line  pressure  of  300  Ib.     The  pressures  were  to  be  plainly 
marked  on  the  valve  by  notches  to  be  used  by  the  operator  as  a 
guide  for  setting  the  handle.     Regulators  were  to  hold  the  pressures 
steadily  within  10  Ib.  of  the  set  amount,  whether  the  play  pipe  were 
open  or  closed.     The  regulator  was  also  to  be  provided  with  a  lock 
whereby  the  handle  could  be  prevented  from  passing  the   150  Ib. 
notch,  but  after  unlocking  could  be  moved  to  the  full  line  position. 
When  wide  open  under  the  maximum  pressure  of  300  Ib.  the  valve 
was  not  to  show  a  loss  of  head  in  excess  of  15  Ib.     The  hydrant  head 
was  to  contain  four  horizontal  outlets  and  one  vertical  outlet,  ea^h 
horizontal  outlet  to  be  provided  with  a  regulator,  and  the  complete 
head  including  four  regulators  was  not  to  weigh  over  110  Ib.     The 
head  and  regulators  were  to  be  designed  for  300  Ib.  working  pressure 
and  were  to  be  tested  with  a  static  pressure  of  600  Ib. 

11  While  the  above  requirements  may  seem  simple  enough,  only 
one  of  the  valves  submitted  by  different  makers  met  the  require- 
ments in  all  essential  points,  a  regulator  designed  especially  for  the 
purpose  by  the  Ross  Valve  Manufacturing  Company  of  Troy.  N.  Y. 
(Figs.  2  and  3). 

12  The  main  regulating  valve  is  inserted  in  an  opening  just  over 
the  hose  connection,  and  is  inclined  outward  at  an  angle  of  20  deg. 
The  opening  is  closed  with  a  plate  carrying  a  pilot  valve  and  a  guide 
for  the  main  valve.     The  pilot  valve  with  its  diaphragm  is  covered 
with  a  spring  chamber,  the  whole  being  held  in  place  by  cap  screws. 


JAMES  B.  SCOTT  187 

The  main  valve  is  balanced  and  is  provided  with  a  flat  seat  and 
leather  face.  The  upper  part  of  the  main  valve  acts  as  an  operating 
piston,  being  provided  with  a  cup  leather  packing.  The  pilot  valve 
is  balanced  against  the  delivery  pressure  by  the  regulator  springs, 
which  are  made  double  to  secure  a  wide  range  of  pressure  in  a  short 
length.  The  top  of  the  spring  chamber  is  revolved  by  the  operating 
handle  attached  to  it,  and  being  provided  with  a  coarse  square 
thread  screw,  less  than  one  revolution  is  sufficient  to  give  the  full 
range  of  pressure  on  the  springs  from  full  open  to  closed.  The  pilot 
valve  is  held  positively  in  the  two  extreme  positions  independently 
of  the  springs  by  stops  at  the  top  and  bottom  of  the  stem.  The  full 
hydrant  pressure  is  admitted  to  the  operating  chamber  of  the  main 
valve  through  a  small  tube  projecting  below  the  seat  of  the  valve. 
This  tube  is  extended  in  order  to  keep  the  entrance  clear  of  the 
varying  velocity  near  the  valve  seat,  which  would  tend  to  vary  the 
flow  of  water  to  the  operating  chamber.  When  the  pilot  valve  is 
open,  water  wastes  from  the  operating  chamber,  the  pressure  is 
lowered  and  the  main  valve  is  opened  by  the  unbalanced  pressure 
below.  When  the  pilot  valve  is  closed  the  full  hydrant  pressure  is 
maintained  in  the  operating  chamber,  and  as  the  area  of  the  operat- 
ing piston  is  somewhat  larger  than  the  area  of  the  main  valve,  the 
pressure  is  unbalanced  in  the  opposite  direction  and  the  main  valve 
is  closed.  Intermediate  positions  of  the  pilot  valve  are  followed  by 
corresponding  movements  of  the  main  valve,  maintaining  the  de- 
livery pressure  within  a  few  pounds  of  the  amount  indicated  by  the 
notch  at  which  the  operating  handle  is  set.  The  main  valve  when 
fully  opened  presents  an  unobstructed  waterway.  The  entire 
mechanism  is  simple  in  design,  easy  to  operate  and  has  proved  entirely 
satisfactory  in  service. 

13  Quantity  of  Water  Available.     The  National  Board  of  Fire 
Underwriters  after  a  careful  study  of  the  situation  recommended 
that  a  total  delivery  of  15,000  gal.  per  min.  should  be  available 
within  any  area  not  exceeding  100,000  sq.  ft.,  at  a  pressure  of  not 
less  than  200  Ib.  at  the  hydrant.     As  installed,  each  hydrant  has  four 
2%-in.  horizontal  and  one  vertical  outlet  for  mounting  a  monitor 
nozzle.     At   present   the   3-in.    hose   is   connected   through   reducer 
couplings,  but  in  the  future  all  hydrants  will  be  equipped  with  3-in. 
outlets  and  connections  to  2%-in.  hose  will  be  made  through  reducers. 

14  The  quantity  of  water  which  can  be  delivered  through  a 
hydrant  is  a  function  of  the  number,  length  and  size  of  hose  lines 


188  BALTIMORE  HIGH-PRESSURE  FIRE  SERVICE 

attached,  and  the  diameter  and  type  of  nozzles.  Assuming  four  lines 
of  3-in.  rubber-lined  hose  each  100  ft.  in  length,  and  200  Ib.  at 
the  hydrant,  with  1%-in.  smooth  nozzles,  each  hydrant  would  de- 
liver 3-800  gal.  per  min.,  or  the  requirement  of  the  underwriters 
would  be  met  by  four  hydrants.  At  least  twice  that  number  of  hy- 
drants are  available  for  every  unit  of  area  mentioned.  If  2-in.  noz- 
zles were  used,  other  conditions  remaining  the  same,  the  discharge 
would  be  4400  gal.  per  min.  at  a  pressure  of  86  Ib.  at  the  base  of  the 
play  pipe,  as  compared  with  108  Ib.  in  the  former  case. 


FIG.  2     PORTABLE  HEAD 

15  At  present  226  hydrants  have  been  installed,  staggered  on 
opposite  sides  of  the  streets,  averaging  about  170  ft.  lineal  spacing. 
In  addition  to  the  normal  locations  at  street  and  alley  intersections, 
the  fire  chief  placed  a  number  of  hydrants  at  special  positions,  to 
meet  local  conditions  of  exposure,  extra  hazard  or  specially  congested 
values. 

16  Design  of  Hydrant.     The  type  of  hydrant  to  be  used  was 
given  careful  study.     It  was  considered  especially  desirable  in  view 
of  the  experience  gained  in  fighting  the  conflagration,  to  be  able  to 


JAMES  B.  SCOTT 


189 


place  a  monitor  or  special  flat  nozzle  directly  on  the  top  of  the 
hydrant,  to  form  a  water  curtain  for  the  protection  of  exposed  prop- 
erty on  the  opposite  side  of  the  street.  Street  intersections  form  a 
specially  desirable  location  for  such  a  purpose,  but  usually  the  corner 
of  the  footway  is  preempted  for  various  other  structures  such  as 
sewer  inlets,  lamp  posts,  trolley  poles,  police  and  fire-alarm  boxes, 
etc.  It  was  soon  evident  that  if  restricted  to  the  ordinary  post  type  of 
hydrant,  it  would  be  impossible  to  secure  suitable  locations,  and  the 


Rubber 
Gasket 


FIG.  3     SECTION  OF  PORTABLE  HEAD 


water-curtain  feature  would  have  to  be  abandoned.  The  flush  hy- 
drant with  portable  head  seemed  to  meet  all  the  conditions  admirably. 
By  the  use  of  this  type,  hydrants  could  be  located  almost  without 
restrictions,  either  in  the  driveway  or  any  part  of  the  footway.  The 
portable  head  was  also  admirably  adapted  to  the  use  of  the  regulating 
valves  on  the  hydrant,  as  the  entire  operating  mechanism,  other  than 
the  main  valve,  could  be  kept  in  the  firemen's  quarters,  instead  of  being 
exposed  to  frost  or  other  injuries  on  the  street. 


190  BALTIMOKE  HIGH-PRESSURE  FIRE  SERVICE 

17  The  portable  head  as  designed  complete  with  four  regulating 
valves,  weighs  ,110  Ib.     In  order  to  provide  against  any  delay  in 
attaching  the  head  to  the  hydrant,  a  special  "bayonet"  joint  was 
designed   (Fig.  2).     The  head  slips  loosely  into  the  barrel  of  the 
hydrant,  and  by  a  twist  of  2i2%  deg.,  a  series  of  interlocking  lugs  on 
the  head  and  barrel  engage  each  other,  and  the  full  section  of  these 
bronze  lugs  is  in  shear  to  resist  the  water  pressure.     The  water  joint 
is  made  by  means  of  a  square  soft  rubber  packing  ring  placed  in  a 
square  groove  on  the  outside  of  the  lower  portion  of  the  head.     The 
groove  is  somewhat  larger  than  the  packing  ring,  and  at  very  low 
pressures  water  leaks  past  the  ring.     At  higher  pressures,  however, 
the  water  presses  the  rubber  closely  against  the  barrel,  and  the  joint 
is  absolutely  tight  at  all  pressures  between  20  and  1000  Ib.     The 
action  is  entirely  automatic,  there  being  no  screws  nor  glands  of  any 
kind  to  be  manipulated.     When  the  water  is  shut  off,  the  ring  con- 
tracts and  the  head  can  then  be  lifted  out  of  the  barrel  without  the 
slightest  resistance.     To  illustrate  the  extreme  simplicity  of  the  de- 
vice, and  the  ease  of  handling,  a  recent  test  by  the  engineers  of 
the  National  Board  of  Fire  Underwriters  may  be  cited.     The  head 
and  operating  key  were  laid  in  the  center  of  the  street,  20  ft.  away 
from  the  hydrant.     Two  firemen  selected  at  random,  picked  up  the 
head  and  key,  ran  to  the  hydrant,  removed  the  two  loose  covers, 
placed  the  head  in  position  and  turned  the  water  on,  all  in  the  space 
of  18  seconds  by  a  stop  watch. 

18  A  small  cast-iron  cover  is  laid  over  the  top  of  the  barrel  to 
protect  it  from  dirt  and  injury,  and  over  this  is  placed  a  larger  cast- 
iron  cover  flush  with  the  pavement.     As  practically  all  the  hydrants 
are  located  on  the  sidewalks  the  cover  is  made  quite  light,  and  if  it 
should  become  frozen  in,  it  can  be  broken  instantly  by  a  blow  from 
the  operating  key. 

19  The  hydrant  proper  is  designed  for  a  clear  waterway  of  28  sq. 
in.  through  the  main  valve.     The  main  valve  closes  with  the  pressure, 
and  an  auxiliary  is  provided,  actuated  by  the  main  valve  stem.     This 
auxiliary  valve  opens  in  advance  of  and  equalizes  the  pressure  before 
the  main  valve  starts  to  open.     A  drip  valve  is  arranged  so  that 
as  the  main  valve  opens  the  drip  is  closed  and  vice  versa,  but  both 
valves  cannot  be  open  at  the  same  time.     Both  the  main  and  auxiliary 
valves  have  conical  leather  faces  and  bronze  seats.     The  barrel  of  the 
hydrant  is  of  soft  grey  iron,  and  all  nuts  and  fittings,  stuffing-boxes, 
etc.,  are  of  bronze.     The  main  valve  stem  is  Tobin  bronze,  and  the 


JAMES  B.  SCOTT 


191 


operating  spindle  is  of  forged  steel.  All  pressure  parts  are  designed 
for  a  working  pressure  of  300  Ib.  with  a  factor  of  safety  of  twelve. 
After  erection  a  field  test  of  600  Ib.  was  made. 

HIGH-PRESSURE  PIPE  LINES 

20     General  Plan.     The  general  plan  of  the  system  is  a  gridiron  of 


<--8  Wrought -Steel  Stand  Pipe, 
Flange  welded  on 


Cast  Steel,  Bronze 
Mounted,  Check  Valve 


V?  Scjuare 


E  I  e  vat  ion 


One  Bronze  Siamese  connection 
on  each  branch  of'Y'connec- 
tfon  Three  3^'  male  fn/ets  each, 
Check  in  each  in/et. 


FIG.  4    FIREBOAT  CONNECTION 

16-in.  mains  crossing  at  intervals  of  approximately  1200  ft.  in  each 
direction,  with  10-in  laterals  in  the  intermediate  streets  spaced  ap- 
proximately 400  ft.  apart.  A  10-in.  branch  is  provided  at  the 
harbor  front  for  connection  with  the  fireboats  (Fig.  4).  All  hydrant 
branches  are  8  in.  There  are  no  dead  ends  on  mains  or  laterals  in 
the  entire  system,  with  the  exception  of  an  extension  on  one  street 


192  BALTIMORE  HIGH-PRESSURE  FIRE  SERVICE 

which  will  be  connected  up  at  the  next  addition  to  the  system. 
From  the  pumping  station  two  24-in.  mains  discharge  into  the  inter- 
sections of  the  16-in.  mains.  In  the  pumping  station  the  24-in. 
mains  are  looped  around  the  rear  of  the  pump  foundations,  thereby 
avoiding  dead  ends  and  by  equalizing  the  stresses  render  unnecessary 
any  heavy  anchorages.  Individual  14-in.  pump  discharges  deliver 
directly  into  the  24-in.  mains  through  welded  necks.  Three  M-in. 
valves  and  an  18-in.  cross  connection  in  the  station,  serve  to  section- 
alize  the  large  main,  so  that  any  portion  may  be  cut  out  without 
putting  more  than  one  pump  out  of  commission.  A  large  rolled  steel 
air  chamber  30  in.  in  diameter  by  20  ft.  high  is  placed  on  each  24-in. 
discharge  main. 

21  Cast-iron  versus  Steel  Pipe.     For  the  service  in  view  it  was 
believed  that  cast-iron  pipe,  usually  employed  for  city  water-mains, 
was  not  a  scientific  application  of  material  for  the  stresses  involved. 
On  the  other  hand,  commercial  rolled  steel  lap-welded  pipe  meets  the 
structural  conditions  much  more  satisfactorily.     With  this  material 
the  pipe  system  becomes  an  engineering  structure,  all  tensile  and 
bending  stresses  are  taken  up  by  the  pipes  themselves  and  the  system 
would  be  entirely  safe  if  laid  on  the  surface  of  the  ground. 

22  The  principal  objection  urged  against  the  use  of  steel  for  this 
purpose  is  the  liability  to  corrosion,  especially  when  complicated  by 
electrolysis  in  city  streets.     After  a  careful  study  of  the  problem,  it 
was  decided  that  the  advantages  of  this  material  outweighed  the  objec- 
tions, for  the  following  reasons : 

a  If  the  entire  pipe  system  had  to  be  renewed  every  ten  years, 
the  steel  would  still  be  more  reliable  and  hence  more 
desirable,  than  cast  iron,  as  the  latter  is  liable  to  fail  by 
breakage  without  previous  warning*  When  deterioration 
of  the  steel  pipe  does  occur,  it  makes  itself  known  by  in- 
crease of  leakage,  which  can  be  detected  and  repairs  made 
gradually,  as  occasion  offers.  By  way  of  a  reductio  ad 
absurdum  it  might  be  argued  that  if  absence  of  corrosion 
be  the  controlling  feature  in  the  selection  of  a  material, 
a  glass  pipe  would  be  the  ideal,  as  it  would  last  forever 
if  not  broken  by  shock  or  bending  stresses. 

b  The  study  of  corrosion  of  steel  has  reached  a  point  where 
it  is  possible  to  say  that  corrosion  is  not  inevitable,  but 
is  due  to  more  or  less  direct  violation  of  certain  well 
defined  principles.  If  steel  can  be  protected  from  the 


JAMES  B.  SCOTT  193 

simultaneous  action  of  moisture,  air  and  acids,  the  causes 
of  rusting  or  corrosion  are  to  a  great  degree  removed, 
regardless  of  the  particular  chemical  theory  held  by  the 
investigator.  Protecting  the  steel  from  the  action  of 
these  three  agents  is  mainly  a  mechanical  proceeding.  A 
permanent,  impervious,  elastic  coating,  which  will  adhere 
closely  to  the  metal  is  the  requirement.  High-grade 
asphalt  applied  "when  both  the  steel  and  the  coating  are 
hot  and  clean,  seems  to  meet  these  conditions  satis- 
factorily. The  specifications  for  the  chemical  composi- 
tion of  the  asphalt  used  were  very  exacting.  Among 
other  conditions  it  was  required  that  a  cubic  centimeter 
of  the  material  should  show  no  action  when  exposed  for 
one  year  in  any  or  all  of  the  following  solutions :  &5  per 
cent  hydrochloric  acid,  -2i5  per  cent  sulphuric  acid,  2>5  per 
cent  potassium  cyanide,  25  per  cent  caustic  soda,  satur- 
ated solution  of  ammonia.  The  pipes  were  thoroughly 
cleaned  and  heated  to  a  temperature  of  300  deg.  fahr. 
and  while  hot  were  dipped  vertically  in  the  bath  of 
asphalt,  which  was  maintained  at  a  temperature  of 
from  350  to  400  deg.  fahr.  The  pipe  was  held  in  the 
bath  for  a  sufficient  length  of  time  and  was  then  drawn 
out  slowly,  at  the  rate  of  5  to  10  ft.  per  min.,  so  that  a 
coating  of  1/32  in.  thickness  was  evenly  distributed  over 
the  entire  surface  of  the  pipe.  Any  damage  to  the  coat- 
ing during  shipment  or  erection  was  repaired  by  the  ap- 
plication of  the  same  material  dissolved  in  a  suitable 
solvent,  and  applied  in  several  coats  at  intervals,  until 
a  satisfactory  thickness  was  obtained.  All  bolts  and  nuts 
were  dipped  in  the  same  solution  before  being  inserted 
in  the  flanges. 

Electrolysis  is  due  to  an  electrical  difference  of  potential 
between  the  metal  and  the  earth  in  contact  with  it,  of 
sufficient  magnitude  to  cause  a  current  flow  from  the 
pipe  to  the  earth.  'Since  the  conflagration  of  1904  the 
City  of  Baltimore  has  required  all  electrical  wires  to  be 
placed  in  the  municipal  conduits,  and  to  protect  the 
cables  from  electrolytic  action  the  city's  electrical  com- 
mission made  a  careful  study  of  the  local  situation.  As 
a  result  the  street  railway  was  compelled  to  rebond  a 


194  BALTIMORE  HIGH-PRESSURE  FIRE  SERVICE 

large  part  of  its  tracks,  copper  cables  being  carried  around 
all  special  work.  In  addition  a  supplementary  copper 
return  covering  the  entire  district  was  installed,  con- 
sisting of  three  bare  copper  cables  having  an  aggregate 
cross-section  of  6,000,000  circular  mils.  An  entirely 
separate  copper  return  was  also  installed  as  a  protection 
for  the  cable  sheaths,  nothing  but  lead  cables  being 
bonded  to  this.  The  cross-section  of  this  latter  varied 
from  1,000,000  to  6,000,000  circular  mils.  As  a  result  of 
this  large  amount  of  copper  in  the  return  circuit,  the 
difference  of  potential  between  the  various  underground 
structures  has  been  reduced  to  a  nominal  figure. 

The  special  joint  designed  for  the  Baltimore  steel  pipe 
line  has  a  resistance  equal  to  6  in.  of  the  pipe  on  the  10- 
in.  size,  and  equal  to  9  in.  on  the  16-in.  pipe.  The  resist- 
ance of  a  bell  and  spigot  lead  joint  is  often  equal  to  4  or 
5  ft.  of  the  pipe. 

d  Finally,  the  current  flow  from  the  pipe  to  the  earth  may 
be  made  very  small  if  a  high  resistance  covering  be  placed 
around  the  entire  pipe  system.  In  the  present  instance 
the  asphalt  coating  furnishes  the  necessary  high  resistance 
envelope. 

23  While  it  is  still  too  early  to  offer  definite  evidence  regarding 
the  life  of  the  pipe  in  question,  pipes  which  have  been  in  the  ground 
for  two  years  have  recently  been  exposed  by  excavation  for  other 
work,  and  have  shown  absolutely  no  signs  of  deterioration,  the  coat- 
ing being  in  perfect  condition. 

24  Pipe.     The  specifications  called  for  lap-welded  pipe  made  of 
soft  open  hearth  steel  .having  the  following  qualities : 

Per  Cent 

Carbon,  not  exceeding 0 . 10 

Phosphorous,  not  exceeding 0 . 04 

Sulphur,  not  exceeding 0 . 05 

Manganese  between 0.35-0.45 

Ultimate  tensile  strength  between  50,000  and  55,000  Ib.  per  sq.  in.;  elastic 
limit  at  least  Y^  ultimate;  elongation  not  less  than  20  per  cent  in  8  in.;  cold  and 
quench  bend  180  deg.  flat. 

25  The  weld  in  the  lap  was  to  be  perfect  and  capable  of  standing 
the  strains  incident  to  the  manufacture  of  bends  and  forming  of 
joints,  without  distress  or  rupture. 


JAMES  B.  SCOTT 


26     The  thickness  of  pipe,  in  inches,  was  as  follows: 


24  in.  Outside  Diameter 

16  in.  Outside  Diameter 

10  in.  Inside    Diameter 

8  in.  Inside    Diameter 


195 


FIG.  5    DETAIL  OP  10-lN.  PIPE  JOINT 

27     Bends  were  generally  of  a  standard  radius  of  5  diameters  of 
pipe.     Length  of  pipe,  in  feet,  laid  was : 

24  in 1,275 

16  in 17,052 

10  in 28,229 

Sin 7,137 

Total 53,693  =  10.2  miles 


196  BALTIMORE  HIGH-PRESSURE  FIRE  SERVICE 

28  Joints.  For  the  present  service  it  was  desired  to  avoid  the 
use  of  rubber  gaskets,  which  would  tend  to  increase  the  electrical 
resistance  of  the  joint.  Copper  gaskets  or  other  metals  dissimilar  to 
the  metal  of  the  pipes,  in  the  presence  of  moisture  and  the  acids  or 
salts  of  the  earth,  would  form  a  voltaic  cell,  and  tend  to  increase  the 
corrosion  due  to  electrical  action.  A  joint  was  therefore  designed  to 
avoid  the  necessity  for  a  gasket  or  joint  cement  of  any  kind. 

£9  The  Baltimore  design  is  a  form  of  universal  joint  (Fig.  5). 
The  end  of  the  pipe  is  flanged  out  into  a  bell  forming  a  zone  of  a 
sphere.  A  soft  cast-iron  ring  is  accurately  turned  in  the  shape  of  a 
torus,  having  the  same  curvature  on  its  exterior  surfaces  as  the  in- 
terior of  the  bell  on  the  pipe  ends.  Loose  flanges  are  placed  on  the 
pipe  back  of  the  bell,  and  when  bolted  up,  draw  the  pipe  bells  up  on 
the  torus  ring  (Fig.  6).  The  pressure  secured  by  the  wedging  effect 
on  the  spherical  surfaces  is  enormous.  If  the  curve  of  the  surfaces 
be  too  flat,  the  metal  of  the -pipe  may  be  cold  rolled,  and  the  flanges 
may  be  pulled  over  the  ring.  By  suiting  the  degree  of  the  curvature 
to  the  diameter  of  the  pipe,  a  safe  combination  is  secured,  and  with 
the  proper  thickness  of  loose  flange,  a  joint  is  secured  which  is  abso- 
lutely water  tight  until  pressures  are  reached  which  exceed  the  elas- 
tic limit  of  the  pipe  or  bolts.  On  the  10-in.  size  this  pressure  is 
about  2200  Ib.  per  sq.  in.  In  the  field  testing,  during  the  installation 
of  the  pipe,  the  specified  test  pressure  was  600  Ib.,  but  during  the 
early  stages  of  the  work,  this  pressure  was  often  largely  exceeded. 

30  The  joints  are  designed  for  a  deflection  of  10  deg.,  or  about  3 
ft.  6  in.  in  a  i20-ft.  length.  On  the  10-in.  size  this  amount  of  deflec- 
tion is  easily  obtainable,  but  on  the  larger  sizes  a  smaller  amount  was 
used,  though  sufficient  to  be  of  considerable  value  in  city  work.  A 
line  of  10-in.  pipe  was  made  up  of  seven  20-ft.  lengths,  and  while  the 
pressure  was  on,  one  end  of  the  line  was  raised  5  ft.  by  means  of  a 
crane,  as  shown  in  Fig.  7.  While  suspended  in  the  air,  supported 
only  at  the  two  ends,  140  ft.  apart,  there  was  practically  no  leakage 
at  any  of  the  joints.  It  is  evident  that  at  least  that  amount  of  trench 
might  be  washed  out  without  interfering  with  the  operation  of  the 
pipe  system  in  the  least  degree.  In  laying  the  pipe  it  was  possible  to 
deflect  it  to  pass  an  obstruction  and  in  one  instance,  after  the  com- 
pletion of  the  work,  owing  to  a  change  of  grade  in  the  sidewalk,  a 
hydrant  branch  50  ft.  long  was  jacked  up  5  in.  at  one  end,  simply  by 
loosening  the  bolts  at  one  joint,  Upon  tightening  these  bolts,  the 
line  tested  free  of  leaks  at  600  Ib. 


JAMES  B.  SCOTT 


197 


FIG.  6    VIEW  OF  PIPE  JOINT  AND  WELDED  NECK 


FIG.  7     SHOP  TEST  OF  PIPE  JOINT 


198 


BALTIMORE  HIGH-PRESSURE  FIRE  SERVICE 


31  The  fact  that  the  pipe  was  laid  in  20-ft.  lengths  means  that 
the  number  of  joints  was  reduced  40  per  cent  in  comparison  with 
cast  iron. 

32  For  deflections  greater  than  could  conveniently  be  made  by 
the  joints,  pipe  bends  were  used.     A  bending  table  was  installed  on 
the  work  by  the  contractor,  and  about  1500  bends  were  made,  or 
150  per  mile  of  pipe  laid.     Bends  of  16-in.  pipe  and  smaller  were  made 


FIG.  8    DETAIL  OF  STRAIGHT  LINE  WELD 


FIG.  9    DETAIL  OF  WELDED  NECK 

on  the  work,  the  24-in.  bends  were  made  at  the  factory  before  ship- 
ment. 

33  For  make-up  pieces  at  intersections  and  in  blocks  between 
valves  or  tees  already  installed,  straight  line  welded  joints  were 
used.  A  special  joint  was  devised  for  this  service,  made  up  as  fol- 
lows: The  end  of  one  pipe  was  accurately  expanded  sufficiently  to 


JAMES  B.  SCOTT  199 

permit  of  its  being  shrunk  over  the  end  of  the  pipe  to  which  it  was 
to  be  joined.  Holes  were  cut  around  the  circumference  of  the  outer 
pipe  or  bell,  and  after  being  heated  it  was  shrunk  on  in  place.  The 
holes  were  then  flowed  up  with  metal  by  the  oxy-acetylene  blow-pipe, 
and  the  end  of  the  bell  was  also  welded  to  the  enclosed  pipe.  With 
this  type  of  joint  the  weld  is  in  shear  and  not  in  tension,  and  it  is 
entirely  feasible  to  make  bends  in  the  pipe  with  the  weld  in  the  arc 
of  the  curve.  Approximately  1500  of  these  straight  line  welds  were 
made  on  the  work,  or  about  150  per  mile  of  pipe  (Fig.  8). 


FIG.  10     CAST  STEEL  SPECIALS 

34  Flanges.     The  loose  ring  flanges  were  of  medium  open  hearth 
steel,  ultimate  tensile  strength  60,000  to  68,000  Ib.     All  flanges  were 
accurately  machined  and  were  drilled  to  template. 

35  Fittings.     The  use  of  steel  pipe  made  it  possible  to  reduce  the 
number  of  fittings  to  a  minimum.     The  hydrant  branches  were  made 
by  welding  necks  to  the  mains  and  laterals.     A  special  neck  weld  was 
used,  made  up  as  follows:     A  hole  was  cut  in  the  pipe,  smaller  than 
the  size  of  the  neck,  and  radial  cuts  were  made  forming  four  narrow 
lugs  which  were  left  projecting  into  the  hole.     The  wider  alternate 
lugs  were  bent  back  to  make  an  opening  large  enough  to  receive  the 
neck  piece.     The  smaller  straight  lugs  formed  a  support  for,  and 
held  the  neck  rigidly  in  place  during  the  welding  process.     The  whole 
joint  was  then  flowed  with  metal  by  an  oxy-acetylene  blow-pipe,  form- 
ing a  joint  as  strong  as  the  original  pipes  (Fig.  9). 

36  The  only  specials  required  were  the  tees  and  crosses  at  the 
intersections  of  the  gridiron,  and  a  valve  connection  piece  used  to 


200 


BALTIMORE  HIGH-PRESSURE  FIRE  SERVICE 


give  a  straight  face  flange  .at  the  valves.  By  the  use  of  the  latter  it 
was  possible  to  use  standard  commercial  valves,  and  the  valves  may 
be  easily  removed  when  necessary  (Figs.  10,  11,  12).  All  fittings 
were  made  of  low  carbon  open  hearth  cast  steel. 

37     Valves     All  valves  are  double-disk  parallel  seat  gates.    Bodies 
are  low  carbon  open  hearth  steel  of  the  same  specifications  as  for 


Note:For  fittings 
reduced  in  run  or 
branch  use  center 
to  face  dimensions  v- 

of  fitting  corresponding    \    ! 
in  size  to  largest  port,  \j 


Bo >// Circle 


B 


30 


B 


22 


* 


R. 


BOLTS 


NO.   DIA. 


16 


24"|  33*|  2y|4l'|  3^p4r|l|1'  |  3*  |  8J"|  2^  27"|  ri'\ttj>    7°    30*    3"  |  24 
FIG.  11     DETAIL  OF  TEES  AND  CROSSES 


fittings.  Bonnets,  disks,  gearing  brackets,  glands  and  packing  boxes 
are  of  semi-isteel.  Stems  are  of  Tobin  bronze,  not  less  than  53,000 
Ib.  tensile  strength.  .Seats,  wedge  mechanism  and  glands  are  of 
bronze.  The  16-in.  and  18-in.  valves  are  geared.  All  street  valves 
are  provided  with  a  stem  nut,  and  a  forged  steel  key  is  placed  in  each 
valve  box.  An  interlocking  arrangement  is  provided  so  that  the  key 


JAMES  B.  SCOTT 


201 


can  be  removed  from  the  nut  only  when  the  valve  is  wide  open. 
This  prevents  the  valves  being  left  closed  or  opened  only  a  few 
turns,  except  in  an  emergency  or  intentionally,  as  the  valve  box 
cover  cannot  be  replaced  while  the  key  is  on  the  nut.  The  24-in. 
valves  are  in  the  pumping  station  and  are  hydraulically  operated. 
All  valves  were  subjected  to  a  shop  test  of  800  Ib.  when  open,  and 
600  Ib.  when  closed. 


-H— > 


Rl 


BOLTS 


NO.   DIA 


8" 


8 


1/4 


16 


32 


16 


tl' 


24     33 


'     Ifc      l£"     3      8|     24  •  27"  I4|>    7'  ,  £3"    30     24      ijfjj 


FIG.  12    DETAIL  OF  VALVE  CONNECTING  PIECE 

38  Valve  Boxes.  The  street  valves  are  treated  as  pieces  of 
mechanism,  subject  to  derangement,  and  hence  are  placed  in  con- 
crete boxes  or  manholes,  42  in.  inside  diameter,  where  they  can  be 
inspected  and  repaired  without  disturbing  the  street  paving.  The 


202 


BALTIMORE  HIGH-PRESSURE  FIRE  SERVICE 


floor  was  first  laid  of  plain  concrete,  with  suitable  drainage  connec- 
tion; then  the  section  enveloping  the  pipe  or  fitting  was  laid  up  with 
concrete  blocks  molded  to  the  standard  radius.  The  upper  clear 
section  was  built  of  reinforced-concrete  rings,  laid  up  without  mortar, 
as  they  are  provided  with  interlocking  projections  on  the  top  and 
bottom  faces,  which  make  the  rings  self-centering.  The  upper  por- 
tion is  made  of  conical  shaped  rings,  forming  the  roof,  and  supporting 
the  cast-iron  cover  frame.  The  blocks  and  rings  were  made  up  in 
quantities  in  metal  molds  and  seasoned  before  being  used.  They 


Street  Level 


Ft^:ViS^^^v^.•^^->•^^A^•y;:^^;^^•s;•^!^;o:•^/5;•:r:-r^^;;.>;n 
K. •.V.'-.^'-V'.'0"1-*'-'-.^ '•'•>'•'.••>.'•' •'•:.A':--.'-'^-';  •'••''  «:-a '•.'.?.•*.*':'•:••.*•.•?•'•.•'' .'-I 

FIG.  13     VALVE  Box  WITH  VALVE  IN  PLACE 

were  quickly  and  easily  assembled  in  the  trench  by  unskilled  labor. 
The  holes  were  back-filled  and  the  street  repaved  in  a  remarkably 
short  time,  an  item  of  considerable  importance  in  a  business  thorough- 
fare as  there  was  no  time  required  for  setting  of  the  concrete  (see  Figs. 
13  and  14). 

LOW-PRESSURE  WATER  SUPPLY 

39     Two  separate  40-in.  mains  from  two  different  river  systems, 
run  direct  to  and  from  the  normal  supply  for  the  high-pressure  pump- 


JAMES  B.  SCOTT 


203 


ing  station.  The  normal  pressure  available  with  the  high^pressure 
draft  included  is  from  30  to  50  lb.,  but  if  by-passed  from  the  middle 
or  high-service  mains,  the  pressure  can  be  carried  at  70  Ib.  A  30-in. 
cast-iron  branch  is  taken  to  the  station  where  it  changes  to  a  30-in. 
rivetted  steel  pipe  inside  the  building. 

40     An  auxiliary  supply  of  brackish  water  from  the  harbor  may 
be  secured  through  a  reinforced-concrete  conduit   3   ft.   sq.   inside. 


FIG.  14    CONCRETE  VALVE  Box  MADE  UP 

The  conduit  is  provided  with  a  large  screen  chamber  at  the  dock, 
and  has  fine  and  coarse  screens  sliding  in  inclined  frames,  and  both 
in  duplicate,  so  that  one  set  of  each  can  be  in  service  while  the  other 
set  is  out  for  cleaning.  The  screen  chamber  is  also  provided  with 
stop  logs  so  that  the  chamber  and  conduit  can  be  pumped  dry  for 
cleaning  out  sediment.  At  the  station  end  the  conduit  terminates 
in  a  large  suction  chamber  located  beneath  the  basement  floor  and 
between  the  pump  foundations.  The  dimensions  of  this  chamber 


204  BALTIMOKE  HIGH-PRESSURE  FIRE  SERVICE 

are  8  ft.  wide,  7  ft.  deep  and  70  ft.  long.  The  gravity  suction  pipes 
enter  the  suction  chamber  through  cast-iron  thimbles  built  into  the 
floor  of  the  basement,  as  the  basement  floor  is  8  or  9  ft.  below  flood 
tide  level. 

41  A  by-pass  from  the  high-pressure  discharge  main  is  led  into 
the  suction  chamber  for  flushing  it,  and  also  forms  a  convenient  dis- 
charge for  the  pumps  during  tests. 

INSTALLATION  OF  PIPE  LINES 

42  Tunnels.     A   considerable   amount   of   tunneling   was   done, 
especially   at   street   intersections,   where   double   track   crossings   of 
the  street  railway  were  frequently  encountered.     On  several  of  the 
busiest  streets  it  was  found  necessary  to  tunnel  for  many  blocks  at 
a  stretch.     In  a  large  number  of  instances  it  was  thought  desirable 
to  tunnel  for  the  hydrant  branches,  as  the  hydrants  being  staggered 
on  opposite  sides  of  the  street,  it  was  necessary  on  every  alternate 
hydrant  to  cross  the  street,  thus  crossing  also  the  railway  tracks, 
pipes,  sewers,  electric  conduits,  etc.     A  segregation  of  these  tunnels 
into  groups  is  as  follows : 

Lineal  Feet 

Intersections  .  : 5,122 

Straight  line ^ 4,623 

Hydrant  connections 2,630 


Total  tunnels  .  . 12,375 

43  Leakage.     For  field  tests  during  the  installation  of  the  pipes, 
the  contractor  furnished  a  portable  testing  set  consisting  of  a  3-h.p. 
4-cycle  gas  engine,  driving  through  a  Morse  chain  a  triplex  plunger 
pump  of  a  capacity  of  5  gal.  per  min.  at  a  pressure  of  1000  Ib.  per 
sq.  in.     Each  street  section  between  valves  was  tested  as  the  work 
was  installed,  and  made  absolutely  tight,  at  the  specified  pressure 
of  600  Ib :     The  section  to  be  tested  was  filled  from  the  ordinary  fire 
hydrants,  after  which  the  test  pump  was  connected  through  a  1-in. 
flexible  steel  hose.     In  the  early  stages  of  the  construction,  the  work- 
men would  frequently  carry  the  pressure  up  to  800  Ib.  and  some- 
time to  100  Ib.,  to  show  interested  spectators  what  the  new  joint 
would  stand.     Afterwards  a  relief  valve  set  for  about  610  Ib.  was 
placed  on  the  pump,  and  the  testing  became  almost  automatic. 

44  After  the  pipe  lines  had  been  completed,  but  before  the  system 
had  been  put  into  commission,  a  pressure  of  about  300  Ib.  was  put 
on  the  pipe  lines  by  the  main  pumps.     There  being  no  hydrants  open, 


JAMES  B.  SCOTT  205 

the  water  was  being  wasted  through  a  by-pass  to  reduce  the  pressure. 
A  suggestion  was  made  to  close  the  pipe  system  off  from  the  pumps 
to  determine  how  long  the  pressure  would  remain.  The  main  24-in. 
valves  were  accordingly  closed,  while  the  pressure  was  at  125  Ib. 
After  a  lapse  of  16  hours  the  gage  registered  95  Ib.,  indicating  that 
the  leakage  was  practically  nothing. 

45  A  duplex  pump  of  100  gal.  capacity  was  installed  to  keep 
up  the  pressure  and  take  care  of  the  leakage  on  the  system.     Since 
the  equipment  has  been  put  into  regular  service  it  has  been  necessary 
to  keep  the  by-pass  valves  open  continually  on  this  pump  in  order 
to  permit  the  plunger  to  move. 

CHOICE  OF  MOTIVE  POWER 

46  General  Considerations.     In  the  preliminary  studies  for  the 
project,  careful  attention  was  given  to  the  design  of  similar  plants 
in  other  cities,  notably  New  York  and  Philadelphia.     In  the  former, 
as  is  well  known,  electric  driven  centrifugal  pumps  are  used.     In 
Philadelphia,  gas  engine  driven,  geared  triplex  plunger  pumps  were 
installed/    In  the  following  discussion  it  should  be  remembered  that 
local  conditions  often  exercise  a  controlling  influence  in  the  decision 
as  to  the  best  form  of  motive  power  for  such  a  plant. 

47  In  Baltimore  the  fundamental  principle  governing  the  design 
of  the  entire  project  was  considered  to  be  reliability  under  the  most 
adverse  conditions  liable  to  be  encountered.     When  it  is  considered 
that  the  safety  of  hundreds  of  millions  of  dollars  vorth  of  property 
is  dependent  upon  the  accurate  functioning  of  each  element,  it  is 
evident  that  no  considerations  of  economy,   either  in   first  cost  or 
operating  expense,  should  be  allowed  to  enter,  if  simplicity  and  cer- 
tainty of  operation  are  thereby  subordinated. 

48  Gas  Engines.     The  gas  engine  is  subject  to  certain  limita- 
tions, which  in  the  case  of  fire  service,  place  it  at  a  distinct  disad- 
vantage. 

a  The  load  factor  of -the  service  is  extremely  low,  being  less 
than  5  per  cent  per  annum,  so  that  the  opportunity  to 
profit  by  the  high  fuel  economy  is  negligible. 

b  Inability  to  carry  more  than  a  small  percentage  of  overload. 

c  In  the  hands  of  expert  operators,  a  well  designed  modern 
gas  engine  is  perhaps  subject  to  no  more  accidents  or 
delays  than  is  a  steam  equipment,  but  certainly  it  is  not 
subject  to  any  less  than  steam.  On  the  contrary,  how- 


206  BALTIMORE  HIGH-PRESSURE  FIRE  SERVICE 

ever,  in  the  hands  of  operators  of  only  average  intelligence 
or  experience,  the  number  of  apparently  trivial  causes 
which  can  result  in  serious  delays  or  damage  is  surpris- 
ingly large  in  a  gas  engine  plant.  In  the  case  of  a  munici- 
pal plant  of  this  type  it  is  useless  to  plan  for  ideal  operat- 
ing conditions,  or  to  assume  that  only  the  highest  grade 
operating  force  will  be  employed. 

49  Electric  Motors.     In  spite  of  its  many  known  advantages,  a 
large  electrical  distributing  system  is  essentially  in  unstable  equilib- 
rium, and  subject  to  complete  interruption  from  very  slight  causes, 
either  natural  or  malicious.     Dependence  for  prompt  renewal  of  the 
service  after  a  shutdown  must  be  placed  in  duplicate  lines  and  equip- 
ment in  the  stations.     But  even  with  these  a   considerable  period 
must  elapse  before  large  electrical  machines  can  be  started  up  and 
brought  into  synchronism.     A  delay  of  this  character  during  the  first 
critical  minutes  of  a  bad  fire  would  be  fatal  to  the  usefulness  of  an 
important  fire  fighting  system.     The  fact  that  a  vital  feature  of  the 
fire  fighting  system  would  be  under  the  control  of  employes  of  an 
outside  corporation  and  not  subject  to  the  discipline  of  the  fire  de- 
partment, with  the  possibility  of  a  conflict  of  authority  at  a  crucial 
moment,  are  all  matters  that  must  be  considered. 

50  Like  the  gas  engine,  the  electric  transmission,  especially  the 
underground  system,  requires  for  its  commercially  profitable  condi- 
tions a  high  load  factor,  but  for  a  different  reason.     To  justify  the 
large  investment  needed,  requires  a  uniform  load  as  near  as  possible 
to  its  capacity,  in  order  that  the  fixed  charges  shall  not  be  out  of 
proportion  to  the  earnings.     Owing  to  the  extremely  low  load  factor 
of  a  fire  station,  its  load  is  a  very  "undesirable"  one  to  a  commercial 
electrical  supply  corporation,  unless  a  "demand"  charge  is  made  suf- 
ficient to  justify  holding  in  reserve  a  definite  proportion  of  the  entire 
equipment  from  the  coal  pile  to  the  electric  cables.     Electrical  plants 
require  the  installation  of  sufficient  equipment  all  along  the  line  to 
supply  the  maximum   annual  peaks.     As   a   fire  is  no  respecter  of 
anybody's  peaks,  it  follows  that  a  fire  station  load  demands  its  own 
separate  power  plant  investment,  whether  the  equipment  is  located 
in  a  commercial  central  station,  or  in  an  isolated  plant  for  its  own 
use. 

51  A  commercial  plant  is  designed  with  a  definite  load  factor 
in  view,  ranging  usually  from  30  to  50  per  cent.     For  these  conditions 
the  most  efficient  equipment  is  justified,  with  all  the  refinements  of 


JAMES  B.  SCOTT  207 

modern  fuel  and  labor  saving  auxiliaries  in  a  large  plant.  If  a  load 
factor  of  only  5  per  cent  had  been  imposed,  however,  a  very  different 
type  of  equipment  would  have  been  selected,  at  a  very  much  smaller 
investment. 

52  The  various  links  in  the  chain  of  an  electrical  supply  equip- 
ment   (not  considering  a  long  distance  transmission)    would  be  as 
follows : 

a  Coal  handling  apparatus 

b  Boilers  and  auxiliaries   (stokers,  stacks,  economizers,  heat- 
ers, etc.) 

c  Steam  turbines  and  auxiliaries 
d  High-tension  generators 
e  High-tension  switching  apparatus 
/  High-tension  cables 
and  at  the  receiving  end 

g  High-tension  switches 
h  High-tension  motors 
i  Centrifugal  pumps 

53  If  a  long  distance  transmission  were  included,  there  would  be 
added  step-up  transformers,  aerial  lines,  a  substation  with  step-down 
transformers  and  switching  apparatus.     If  low-tension  motors  were 
used,  additional  transformers  would  be  required. 

54  An  isolated  steam  pumping  station,  designed  for  the  purpose, 
eliminates  at  once  five  of  the  above  links,  namely,  items  d,  e,  f,  g  and 
hf  and  concentrates  the  entire  operation  in  one  building,  under  the 
direct  control  of  the  fire  fighters  themselves. 

55  Finances  of  8 team  and  Electrical  Operation.     Expressed  in 
dollars  and  cents  the  argument  becomes  as  follows : 

ELECTRIC  PUMPS  (New  York  Type) 
Investment 

5  motor-driven  pumps  (rated  capacity  3000  gal.  per 

min.),  switchboard,  etc $112,500 

Building  and  pump  foundations 84,000 

$196,500 
Operation 

Maintaining  pressure  continually 
8760  hr.  less  100  hr.  = 

8660  hr.  at  100  kw 866,000  kw-hr. 

Fire  service,  100  hr.  per  annum 

3150  kw.  demand 315,000  kw-hr. 

1,181,000  kw-hr. 


208  BALTIMORE  HIGH-PRESSURE  FIRE  SERVICE 

Service  charge,  maximum  demand  = 3150  kw. 

Central  station  investment,  3150  kw.  at  $75 $236,000 

Underground  cable  (Baltimore  conditions) 40,000 

Cash  requirements 276,000 

Underwriting  at  90 .     31,000 

Total  investment $307,000 

Fixed  charges  on  $307,000 

Interest at  5  per  cent 

Depreciation at  5  per  cent 

Profit at  5  per  cent 


Total 15  per  cent  $46,000 

Underground  conduits,  duct  rental  (Baltimore  condi- 
tions)         1,300 

Total  service  charge $47,300 

Operating  expenses 

Service  charge $43,700 

Meter  charge,  1,181,000  kw-hr.  at  1  cent 11,810 

Salaries,  station  operating  force 10,650 

Supplies,  lubrication  and  repairs 1,000 

$67,160 
Fixed  charges  on  $196,500 

Interest  at  4  per  cent $7,860 

Depreciation  at  5  per  cent 9,825 


17,685 

Total  annual  expense,  electrical  plant $84,845 

STEAM  PUMPS 
Investment 

Four  4000-gal.  pumps  and  auxiliaries .- .  .  .   $86,000 

Boilers  and  auxiliaries 70,000 

Piping,  steam  and  auxiliary  water 30,000 

$186,000 
Building  and  machinery  foundations 125,000 


$311,000 
Operation 

Coal  consumption 

Banking  fires,  8760  hr.— 
100  hr.=  8660  hr.= 

360  days  at  6  tons  per  day 2160  tons 

Fire  service,  100  hr.  per  annum  at  5  tons  coal  per 
hour .  .  500  tons 


Total..  2660  tons 


JAMES  B.  SCOTT  209 

Operating  expenses 

Coal,  2660  tons  at  $3.30 $8,778 

Salaries,  station  operating  force 13,350 

Supplies,  lubrication  and  repairs 2,000 


$24,128 
Fixed  charges  on  $311,000 

Interest  at  4  per  cent '. $12,440 

Depreciation  at  5  per  cent 15,550 


27,990 
$52,118 


SUMMARY 

Total  annual  expense,  electrical  plant $84,845 

Total  annual  expense,  steam  plant 52,118 


Total  annual  saving $32,727 

This  saving  capitalized  at  9  per  cent  represents  an  investment  by  the  city  of 
$363,630,  considerably  more  than  the  first  cost  of  the  steam  plant  in  the  above 
comparison. 

STEAM  PUMPING  STATION 

56  Pumps.     The  Baltimore  plant  is  designed  for  four  main  units 
of  4000  gal.  per  min.  rated  capacity,  at  a  piston  speed  of  300  ft.  per 
min.  and  making  50  r.p.m.     Three  main  engines  have  been  installed 
and  are  in  operation  at  present;  the  fourth  unit  will  be  added  in  the 
near  future  (Fig.  15). 

57  In  line  with  the  policy  of  designing  all  parts  of  the  system 
with  a  first  requisite  of  simplicity  and  reliability,  the  main  units  each 
consist  of  a  horizontal,  twin,  simple,  non-condensing,  crank  and  fly- 
wheel, plunger  pumping  engine.     The  water  ends  are  attache.d  directly 
to  the  engine  frames,  at  opposite  ends  from  the  steam  cylinders,  the 
crankshaft  being  in  the  center  (Fig.  16). 

58  The  steam  cylinders  are  fitted  with  standard  Corliss  valve 
gears,  having  double  eccentric  long  range  cut-offs.     The  cut-offs  of 
both  cylinders  are  under  the  direct  control  of  the  speed  and  pressure 
regulators,  and  are  also  provided  with  hand  control. 

59  Each  engine  was  liberally  designed  for  a  continuous  working 
pressure  of  300  Ib.  per  sq.  in.  on  the  water  ends,  with  a  test  pressure 
of  600  Ib.  static.     Injection  parts  were  designed  for  a  variation  of 
pressure  from  70  Ib.  direct  to  a  suction  lift  of  15  ft.  of  salt  water. 
All  steam  parts  were  designed  for  maximum  working  pressure  of  200 
Ib.,  but  the  normal  working  pressure  is  only  125  Ib. 


210  BALTIMORE  HIGH-PRESSURE  FIRE  SERVICE 

60  Each  engine  is  fitted  with  speed  and  pressure  governors.     The 
speed  governor  is  driven  by  a  noiseless  chain  belt,  and  acts  directly 
on  the  cut-off  valves  of  both  cylinders.     The  pressure  governors  are 
identical  in  principle  with  the  regulating  valves  used  on  the  hydrants, 
and  were  also  furnished  by  the  Ross  Valve  Manufacturing  Company. 

61  The  net  effective  valve  area  between  the  openings  of  the  valve 
seats  on  each  suction  and  discharge  deck  is  30,8  sq.  in.  or  2-2-0  per 
cent  of  the  cross  sectional  area  of  the  plungers.     The  valves  are  3~y2 
in.  in  diameter  and  are  composed  of  rubber  with  brass  backing  plates ; 
the  seats  are  of  bronze,  screwed  into  the  valve  decks  on  a  taper  and 
faced  off  after  being  placed  in  the  decks. 

62  Auxiliaries.     To  take  care  of  the  leakage  in  the  pipe  system 
and  maintain  a  pressure  of  150  lb.,  as  well  as  to  provide  for  the  first 
draft  from  the  hydrants  before  the  main  pumps  are  in  action,  a 
1000-gal.  per  min.  pump  was  installed.     This  is  a  horizontal,  duplex, 
direct-acting,     compound,     non-condensing,     center-packed     plunger 
pump,  giving  its  rated  capacity  at  a  piston  speed  of  100  ft.  per  min. 
While  the  pump  was  designed  for  a  normal  working  pressure  of  150 
lb.  on  the  water  end,  and  for  125  lb.  on  the  steam  end,  all  pressure 
parts  were  designed  to  withstand  a  continuous  pressure  of  300  lb. 
on  the  water  end  and  200  lb.  on  the  steam  end,  so  that  the  pump 
could  be  left  in  service  under  the  maximum  pressures  of  the  main 
pumps  without  injury.     Owing  to  the  leakage  on  the  system  being 
so  small,  the  pump  is  inconveniently  large  for  the  purpose  intended, 
and  it  has  been  necessary  to  keep  the  delivery  b}^-passed  continuously 
in  order  to  keep  the  plunger  in  motion. 

6-3  In  order  to  maintain  the  air  in  the  delivery  air  chambers, 
there  are.  provided  two  steam  driven,  crank  and  flywheel,  two-stage 
air  compressors,  each  having  a  capacity  of  50  cu.  ft.  of  free  air  per 
min.  against  a  pressure  of  450  lb.  There  is  also  provided  a  wrought 
steel  storage  tank  30  in.  in  diameter  by  5  ft.  high.  There  are 
two  large  air  chambers  on  the  24-in.  discharge  mains,  in  addition  to 
those  on  the  pumps.  The  former  are  made  of  lap-welded  rolled  steel 
pipe,  y2  in.  thick,  30  in.  in  diameter  and  20  ft.  high.  The  ends  are 
bumped,  riveted  and  welded  to  the  pipe.  Two  sets  of  glass  gages  are 
attached  through  bosses  welded  on  the  sides. 

64  For  priming  purposes,  when  lifting  from  the  harbor,  there  is 
provided  one  vertical,  steam  driven,  crank  and  flywheel  single-stage, 
dry  vacuum  pump,  6  in.  steam,  10  in.  air,  and  6  in.  stroke.  This 
pump  is  connected  to  the  harbor  suctions  through  a  large  separator 


JAMES  B.  SCOTT 


211 


212 


BALTIMORE  HIGH-PRESSURE  FIRE  SERVICE 


JAMES  B.  SCOTT  213 

tank  at  the  top  of  a  40  ft.  riser,  to  prevent  water  being  drawn  over 
into  the  air  cylinder. 

65  The  plant  is  provided  with  a  four-motor,  electric  traveling 
crane,  main  hoist  20  tons  capacity,  auxiliary  hoist  5  tons.    For  light- 
ing the  station  and  for  the  operation  of  the  electrically  driven  auxil- 
iaries, there  are  provided  two  non-condensing  steam  turbo-genera- 
tors. 

66  Tests  and  Duty  Trials.     The  specifications  for  the  pumps  pro- 
vided for  an  endurance  and  capacity  test  of  24  consecutive  hours. 

67  A  normal  load  duty  trial  was  also  specified,  covering  a  period 
of  12  hours;  steam  pressure  at  the  throttle  125  Ib.     The  steam  con- 
sumption was  to  be  based  on  the  feedwater  supplied  to  a  separate 
boiler  blanked  off  from  all  other  sources  of  supply.     The  measured 
consumption  was  to  include  all  jacket  steam,  but  not  that  required 
for  boiler  feed  pumps  and  other  auxiliaries,  nor  separator  condensa- 
tion and  drips  from  the  steam  piping  on  the  boiler  side  of  throttle. 

68  In  order  to  avoid  the  insertion  of  a  water  meter  in  either  the 
main  suction  or  discharge  lines,  a  venturi  meter  is  by-passed  around 
a  gate  valve  in  the  30-in.  city  water  supply.    As  the  pump  discharge 
can  be  accurately  measured  from  the  record  of  the  pump  strokes  for 
a  given  period,  when  the  slip  is  known,  in  this  case  the  venturi  meter 
is  only  used  to  calibrate  the  slip  of  a  single  pump,  and  therefore  has 
a  capacity  only  equal  to  one  pump. 

69  The  duty  specified  is  70,000,000  ft.-lb.  per  1000  Ib.  of  dry 
steam,  under  normal  operating  conditions  of  300  gal.  per  min.  dis- 
charge, against  a  head  of  250  Ib.,  with  30  Ib.  pressure  on  the  suction, 
and  125  Ib.  of  steam  at  the  throttle. 

70  Boilers.     The  plant  is  designed  for  four  boilers,   each  set 
singly,  and  each  provided  with  a  separate  stack  carried  on  structural 
steel  supports  directly  over  the  setting.     At  this  time  only  three  boil- 
ers have  been  installed,  the  fourth  will  be  added  in  the  near  future 
(Fig.  17). 

71  The  boilers  are  of  the  horizontal,  inclined,  straight  tube  type, 
with  forged  steel  water  legs  reinforced  with  hollow  staybolts.     Each 
boiler  contains  6800  sq.  ft.  of  heating  surface,  and  three  36-in.  drums. 
All  pressure  parts  are  designed  for  200  Ib.  working  pressure.     Each 
boiler  is  capable  of  a  continuous  evaporation  of  45,000  Ib.  of  water 
from  and  at  21,2  deg.  fahr.  into  commercially  dry  steam,  when  burn- 
ing semi-bituminous  coal  of  approximately  14,500  B.t.u.,  with  forced 


214  BALTIMORE  HIGH-PRESSURE  FIRE  SERVICE 

draft  not  exceeding  3  in.  of  water  in  the  ashpit,  or  the  equivalent  of 
1  boiler  h.p.  from  3.77  sq.  ft.  of  heating  surface. 

72  As  the  actual  time  during  which  the  boilers  will  be  in  active 
service  will  probably  average  only  about  100  hours  per  annum,  the 
plant  was  designed  for  carrying  banked  fires  for  a  large  proportion 
of  the  time,  with  the  least  possible  loss  from  radiation.     The  top, 
sides  and  rear  of  each  boiler  are  enclosed  in  an  air-tight  steel  plate 
casing.     The  hotter  portions  of  the  side  walls,  amounting  to  about 
20  per  cent  of  the  area  of  these  walls,  are  covered  with  2  in.  of  mag- 
nesia blocks  inside  the  casing.     The  casing  plates  are  supported  on  a 
framework  of  steel  angles,  attached  to  the  structural  steel  members 
supporting  the  boilers  and  stacks.     These  angles  act  also  as  buck- 
staves  for  the  settings.     Access  and  dusting  doors  are  provided  where 
necessary,  which  are  hinged  at  the  top  and  close  tightly  on  inclined 
faces. 

73  The  boilers  are  set  in  the  reverse  direction  from  the  usual 
method,  that  is,  with  the  low  end  of  the  tubes  over  the  furnace.     The 
front  portion  of  the  furnace  is  covered  with  a  flat  fire  brick  arch, 
made  of  split  tiles  encircling  and  supported  by  the  lower  row  of 
tubes.     When  under  fire,  there  is  presented  to  the  furnace  gases  an 
incandescent  fire  brick  surface,  instead  of  the  customary  cool   iron 
surface  of  the  tubes.     The  first  pass  of  the  gases  between  the  tubes 
is  at  the  extreme  rear  of  the  boiler,  thus  providing  a  furnace  area 
equal  to  the  entire  floor  space  occupied  by  the  boiler  inside  the  set- 
ting, and  making  it  possible  to  force  the  boiler  to  90  per  cent  over 
the  customary  rating  without  imperfect  combustion.     A  special  grade 
of  fire  brick  was  used  for  the  furnace  lining,  which  under  a  change  of 
temperature  of  3100  deg.  fahr.  shows  an  expansion  or  contraction  of 
less  than  0.01  in.  per  ft. 

74  Forced  Firing.     The  conditions  of  fire  service  require  that  the 
boilers  shall  be  capable  of  changing  from  banked  fires  to  the  maximum 
capacity  in  the  shortest  possible  time.     The  intervals  specified  were 
as  follows:  one-half  rated  capacity  in  5  minutes;  full  rated  capacity 
in  12  minutes;  overload  of  75  per  cent  in  £0  minutes. 

75  Choice  of  Fuel.     The  above  conditions  made  imperative  the 
use  of  a  gaseous  fuel,  or  fuel  oil,  or  forced  draft  with  coal.     The 
possibility  of  the  use  of  a  combination  of  two  of  these  was  also  con- 
sidered.    With  gas  at  90  cents  per  1000  ft.,  this  material  was  aban- 
doned.    The  use  of  crude  oil  was  given  careful  study.     Due  to  the  fact 


JAMES  B.  SCOTT  215 

that  economy  of  operating  expense  was  not  the  primary  considera- 
tion, the  problem  was  somewhat  simplified. 

76  As  the  plant  is  located  in  a  wholesale  district  where  high  val- 
ues of  stock  are  common,  it  would  have  been  necessary  to  have  stored 
the  main  supply  of  oil  underground.     Ample  space  for  this  purpose 
existed  in  the  wide  water  front  street  about  200  ft.  from  the  station. 
On  the  other  hand,  experience  has  demonstrated  that  oil  should  be 
fed  to  the  burners  only  by  gravity  from  an  overhead  storage  of  suit- 
able capacity.     Experience  has  also  shown  that  in  spite  of  all  pre- 
cautions, an  oil  storage  tank  will  in  all  probability,  sooner  or  later, 
take  fire.     It  was,  of  course,  possible  to  design  a  fireproof  barrier 
which  would  prevent  the  fire  doing  damage  to  adjoining  property. 
It  was  believed,  however,  that  in  a  plant  designed  for  fighting  con- 
flagrations, the  possibility  of  an  oil  fire,  with  its  huge  volumes  of 
dense  black  smoke,  would  not  tend  to  popularize  the  system,  even 
if  the  fire  proved  to  be  entirely  harmless.     In  spite  of  its  recognized 
advantages  in  ease  of  handling  and  quick  firing,  the  use  of  fuel  oil 
was   therefore   definitely   abandoned,    and   coal   was   adopted.     The 
introduction  of  natural  gas  from  the  West  Virginia  fields  has  been 
under  consideration  for  some  years,  and  if  this  should  be  accom- 
plished, it  would  make  an  admirable  fuel  for  the  purpose,  either  alone 
or  as  supplementary  to  the  coal  furnaces. 

77  Automatic  Mechanical  Stokers.     The  use  of  coal  made  neces- 
sary also  the  use  of  forced  draft.     In  addition,  it  was  desirable  that 
during  the  periods  of  banked  fires,  there  should  be  maintained  a  full 
bed  of  ignited  coal,  requiring  only  the  air  blast  to  force  the  fire  to  the 
highest  rate  of  combustion.     The  underfeed  type  of  stoker  seemed  to 
meet  these  conditions  very  satisfactorily.     A  large  body  of  coal,  ap- 
proximately 1000  lb.,  can  be  carried  in  each  furnace,  a  part  of  this 
coal  incandescent,  a  part  coked  and  a  part  in  the  process  of  coking. 
This  represents  about  14,500,000  B.t.u.  in  storage  ready  for  use  011  a 
few  minutes'  notice.     As  a  further  heat  storage,  the  steam  pressure, 
which  is  ordinarily  carried  at  about  150  lb.,  can  be  raised  to  200  lb., 
immediately  upon  the  receipt  of  an  alarm.     As  the  normal  operating 
pressure  is  only  from  125  to  150  lb.  at  the  pump  throttles,  by  the 
time  the  hose  companies  can  reach  the  hydrants  and  attach  the  hose, 
and  put  a  sufficient  draft  on  the  pumps  to  pull  the  steam  down  to 
normal,  the  furnace  fires  will  be  ready  to  respond  to  any  demand. 

78  Each  boiler  is  equipped  with  four  underfeed  stokers,  and  each 
stoker  unit  is  capable  of  burning  efficiently,  without  smoke,  1000  lb. 


216  BALTIMORE  HIGH-PRESSURE  FIRE  SERVICE 

of  coal  per  hour.  For  the  four  boilers  a  duplicate  blower  equipment 
is  installed,  each  consisting  of  a  full  housed  steel  plate  fan  of  suffi- 
cient capacity  to  operate  the  four  boilers  at  75  per  cent  overload. 
Each  blower  is  driven  by  a  direct-coupled  vertical  steam  engine,  and 
is  connected  to  the  main  air  pipe  line,  and  by  means  of  dampers 
either  blower  can  be  used  to  serve  any  or  all  the  boilers. 

79  To  regulate  the  supply  of  both  fuel  and  air  in  the  proportion 
required  for  complete  combustion  under  all  rates  of  firing,  the  stokers 
are  provided  with  automatic  regulators  actuated  by  the  boiler  pres- 
sure.    Provision  is  also  made  for  hand  regulation,  so  that  it  is  pos- 
sible to  anticipate  sudden  demands  for  steam  upon  receipt  of  an  alarm, 
and  also  for  decreasing  the  supply  of  both  fuel  and  air  when  the  de- 
mand for  forced  firing  has  passed. 

80  Stacks.     Each  boiler  is  provided  with  a  separate  steel  stack 
located  directly  over  the  boiler  which  it  serves.    Each  stack  is  72  in. 
diameter  by  125  ft.  above  the  boiler  room  floor,  and  is  carried  by 
structural  steel  framing  from  the  boiler  foundations.     The  stacks 
are  unlined. 

81  Coil  Handling  and  Storage.     'Semi-bituminous  run  of  mine 
coal  is  used  almost  entirely  for  steaming  purposes  in  the  vicinity  of 
Baltimore.     In  this  instance  the  coal  is  delivered  in  carts,  the  total 
annual  consumption  being  too  small  to  justify  mechanical  handling 
under  existing  conditions.     The  coal  is  dumped  on  a  grating  over  an 
opening  in  the  sidewalk,  the  mesh  being  4  in.  sq.     Large  lumps  are 
broken  up  with  a  maul,  as  with  the  type  of  stoker  in  use  there  is  no 
necessity  for  the  coal  to  be  crushed  to  smaller  sizes.     Below  the  grat- 
ing there  is  a  dumping  hopper  which  receives  the  coal  and  delivers 
it  to  the  lower  run  of  a  bucket  elevator.     The  elevator  is  a  double 
strand  link  belt  with  V-shaped  buckets,  16  in.  by  15  in.,  dumping 
by  gravity.     The  outfit  has  a  capacity  of  25  tons  per  hour  with  uni- 
form feed. 

82  The  coal  is  delivered  into  reinforced-concrete  bunkers  with 
inclined  bottoms,  located  directly  over  the  fireroom.     The  bunkers 
have  a  capacity  of  150  tons  without  trimming,  or  sufficient  to  operate 
the  entire  plant  at  its  maximum  capacity  for  30  hours.     Coal  can 
also  be  delivered  from  carts  directly  on  to  the  boiler  room  floor,  so 
that  the  operation  of  the  plant  is  not  dependent  upon  the  coal  hand- 
ling equipment  nor  the  storage  supply. 

83  Boiler   Feedwater.     Boiler    feedwater    is    normally    supplied 
from  the  city  mains  under  30  to  50  Ib.  pressure,  sufficient  to  deliver 


JAMES  B.  SCOTT 


217 


218  BALTIMORE  HIGH-PRESSURE  FIRE  SERVICE 

to  the  open  heaters  in  the  gallery  of  the  engine  room,  without  pump- 
ing. In  the  event  of  an  interruption  to  the  city  supply,  the  feed- 
water  can  be  taken  from  a  reserve  supply  stored  in  steel  tanks  in  the 
basement  under  the  boilers.  For  lifting  from  the  storage  tanks  and 
delivering  to  the  heaters  a  duplicate  set  of  low-service  duplex  steam 
pumps  is  provided. 

84  To  avoid  the  loss  of  efficiency  in  the  boilers  due  to  scale,  and 
the  necessity  for  taking  the  boilers  out  of  service  for  considerable 
periods  while  removing  scale,  a  double  unit  hot  process  purifier  and 
heater  of  the  Cochrane  type  was  installed,  each  half  of  ample  capacity 
to  handle  the  consumption  of  the  entire  plant. 

85  The  heaters  are  located  in  a  gallery  in  the  engine  room,  di- 
rectly over  the  boiler  feed  pumps,  thereby  providing  a  gravity  head 
of  2$  ft.  for  the  hot  water  to  the  pump  suction.     There  are  three 
duplex,  outside  end  packed  boiler  feed  pumps,  brass  fitted  and  with 
pot  valves,  designed  for  300  Ib.  pressure. 

86  In  addition  to  the  above,  each  boiler  is  provided  with  a 
Metropolitan  Model  0  No.  7%  injector,  capable  of  supplying  the 
maximum  evaporation  of  the  boiler  when  lifting  from  the  storage 
tanks  in  the  basement. 

87  Foster  excess  governors  are  provided  on  the  feed  pumps,  and 
Williams  regulators  on  the  boilers. 

88  Piping.     A  12-in.  steam  header  forms  a  closed  ring  around 
the  plant,  with  long  radius  expansion  bends  at  all  changes  in  direc- 
tion (Figs.  18,  19,  20).     A  sufficient  number  of  gate  valves  are  placed 
in  the  header  to  sectionalize  it,  so  that  any  portion  may  be  cut  out 
without  disabling  more  than  one  boiler  or  one  pump.     Pipe  is  full 
weight,   lap  welded,   soft  open  hearth  steel.     To  provide  an  inde- 
pendent header  for  the  station  auxiliaries,  a  6-in.  cross  connection  is 
made  across  the  center  of  the  main  header,  which  is  capable  of  being 
fed  from  either  side  of  the  main  header,  in  case  of  accident  to  the 
other.     No  fittings  whatever  are  used  in  the  main  line,  all  branches 
being  taken  from  interlocked  welded  necks.     Boiler  branches  are  pro- 
vided with  non-return  valves  at  the  boiler  nozzles  and  gates  at  the 
header  end.     Van  Stone  flanges  are  provided  for  connections  to  the 
valves  and  receivers,  which  are  located  so  as  to  avoid  as  far  as  pos- 
sible the  necessity  for  any  additional  joints  in  the  line.     Wrought 
steel  receiver  type  separators  are  installed  at  the  low  points  on  each 
side  of  the  header. 

89  The  exhaust  system  is  extremely  simple,  a  multi-port  back 


JAMES  B.  SCOTT 


219 


220 


BALTIMORE  HIGH-PRESSURE  FIRE  SERVICE 


JAMES  B.  SCOTT  221 

pressure  valve  on  the  18-in.  riser  serves  to  turn  all  the  exhaust  into 
the  heaters  at  light  loads,  and  provides  a  direct  path  to  the  atmos- 
phere when  the  steam  is  in  excess  of  the  heater  requirements. 

90  Building.     The  site  of  the  pumping  station  is  a  lot  69  ft. 
front  by  137  ft.  deep,  running  back  to  a  16  ft.  alley.     The  property 
immediately  adjoining  on  the  two  sides  is  occupied  by  warehouses 
carrying  more  or  less  inflammable  stocks.     On  the  opposite  side  of 
the  alley  the  same  conditions  exist.     All  foundations  for  the  pumping 
station  and  machinery  were  designed  to  rest  on  caissons  carried  to 
the  gravel,  so  that  it  was  necessary  to  underpin  the  walls  of  both  the 
adjoining  buildings. 

91  All  structural  portions  of  the  building,  including  columns, 
girders,  beams,  floor  and  roof  slabs,  and  all  walls  except  the  front, 
are  of  reinforced  concrete.     The  adjoining  buildings  on  the  sides  are 
from  10  to  20  ft.  higher  than  the  station  roof,  so  the  roof  girders, 
beams  and  slabs  were  designed  to  withstand  the  shock  of  falling 
walls  in  case  of  fire.     The  side  walls  are  not  less  than  8  in.  thick  in 
any  part,  and  have  no  openings  whatever.     The  rear  wall  is  the  same, 
except  that  there  is  one  door  at  the  level  of  the  boiler  room  floor. 

9i2  For  access  to  the  men's  quarters  an  automatic  push-button 
electric  elevator  is  installed,  in  addition  to  the  stairway.  Standard 
brass  sliding  poles  are  also  provided  for  quick  response  to  an  alarm. 
The  quarters  are  located  over  the  front  of  the  engine  room,  and  in- 
clude a  dormitory,  dressing  room,  bath,  toilet  and  reading  rooms. 
In  addition,  a  private  bedroom,  bath,  parlor  and  office  are  provided 
for  the  chief  engineer. 

93  In  addition  to  the  fireproof  construction  of  the  building, 
further  fire  fighting  equipment  for  the  protection  of  the  station  con- 
sists of  a  water  curtain  for  the  exposed  front  and  rear,  and  two  8-in. 
standpipes,  to  be  fitted  with  monitor  nozzles.     A  dangerous  fire  in 
the  immediate  vicinity  of  the  station  could  thus  be  effectively  fought 
from  the  roof  as  well  as  from  the  ground. 

94  Signaling  System.    In  addition  to  the  regular  fire  alarm  cir- 
cuit, a  separate  telephone  circuit  runs  to  the  pumping  station  from 
fire  alarm  headquarters,  fire  department  headquarters,  and  the  chief's 
night  quarters.      This  circuit  connects  to  contacts  for  portable  tele- 
phones in  each  fire-alarm  box  in  the  high-pressure  district.     In  addi- 
tion to  the  regular  Morse  key  and  sounder  there  are  contacts  for  a 
telephone  connection  in  each  box,  over  the  fire  alarm  circuit.    Finally 
there  is  available  the  regular  public  telephone  service. 


222  BALTIMORE  HIGH-PRESSURE  FIRE  SERVICE 

CONSTRUCTION  COSTS 

PORTABLE  EQUIPMENT 

2  automobile  hose  wagons  at  $5000 $10,000 

8000  ft.  3  in.  hose  at  $1 8,000 

30  portable  heads  and  regulators  at  $385 11,550 


Total $29,650 

PIPE  SYSTEM 

Material  delivered  Baltimore 

Hydrants,  226  at  $100 $22,600 

8  in.  pipe,  7137  ft.  at  $2.35 16,700 

.  10  in.  pipe,  28,229  ft.  at  $3.10 87,700 

16  in.  pipe,  17,052  ft.  at  $5.25 89,600 

24  in.  pipe,  1275  ft.  at  $10 12,750 

8  in.  gate  valves,  6  at  $100 600 

10  in.  gate  valves,  193  at  $130 25,000 

16  in.  gate  valves,  90  at  $210 18,900 

18  in.  gate  valves,  2  at  $300 600 

24  in.  gate  valves,  3  at  $1,000 3,000 

Air  and  relief  valves 200 

Low  pressure  gates,  2-30  in 500 

Suction  pipe,  400  ft.  cast  iron,  30  in.,  at  $4 ...  1,600 

Steel  air  chambers,  2-30  in.,  at  $500 1,000 

Venturi  meter 500 

Cast  steel  specials 17,500 


$298,750 
INSTALLATION 

Laying  pipe,  including  placing  valves,  fittings,  hy- 
drants, etc. 

8  in.  pipe,    7,137  ft.  at  $0.70 $4,996 

10  in.  pipe,  28,229  ft.  at    0.75 21,200 

16  in.  pipe,  17,052  ft.  at    1.15 19,600 

24  in.  pipe,  1,275  ft.  at    1.75 2,230 

Pump  connections  in  station 6,000 

Laying  30  in  c.  i.  suction 3,400 

Tapping  40  in.  main 1,500 

Concrete  valve  boxes,  293  at  $30 8,790 

Excavation,  back  filling  and  rubble  paving 

41,318  ft.  open  trench,  at  $3.84 158,600 

12,375  ft.  tunnel,  at  $4.08 50,400 

Improved  paving,  6650  sq.  yd.,  at  $1.50 10,000 

Superintendence,  use  of  tools,  etc 50,000 


$336,716 

$635,466 


JAMES  B.  SCOTT 


223 


224  BALTIMORE  HIGH-PRESSURE  FIRE  SERVICE 

PUMPING  STATION 

Site  and  preliminary  work $37,730 

Building,  including  machinery  foundations,  and  men's  quar- 
ters      124,800 

Harbor  intake  and  screen  chamber 10,000 

Equipment 

Four  4000  gal.  pumps $82,000 

One  1000  gal.  pump 3,500 

Auxiliary  pumps 4,250 

Feedwater  heaters  and  purifiers 4,750 

4  boilers  and  settings,  27,200  sq.  ft.  heating 

surface 33,000 

16  underfeed  stokers,  blowers,  air  piping,  etc .  .   18.000 

4  steel  stacks  and  supports 8,000 

Coal  handling  apparatus 7,000 

Turbo-generators  and  switchboard 4,500 

Electric  crane 4,000 

Steam  and  auxiliary  water  piping 30,000 


$199,000 

371,530 


Miscellaneous 

Signal  system,  cables,  etc $1,500 

Furnishings  for  men's  quarters 500 

Incidentals 5,000 


7,000 
Engineering 50,000 


Total  cost  of  construction $1,093,546 

95  Operating  Department.     The  Board  of  Fire  Commissioners  is 
the  executive  head  of  the  operating  department,  acting  through  the 
department  chief.     The  operation  and  maintenance  of  the  pumping 
station  and  the  maintenance  of  the  pipe  lines,  hydrants  and  port- 
able heads   are   directly  under  the   supervision   of  the   department 
superintendent  of  machinery,   Thomas   H.   Meushaw.     The  mainte- 
nance work  for  the  pipe  line  is  in  charge  of  a  general  foreman,  John 
Rudolph,  who  was  chief  inspector  for  the  city  during  the  early  part 
of  the  installation,  and  general  foreman  for  the  contractor  during 
the  latter  portion  of  the  work. 

96  The  operating  force  at  -the  pumping  station  is  in  charge  of  a 
resident  engineer  and  five  assistant  engineers,  with  four  stokers  and 
two  general  assistants,  all  organized  as  a  fire  company.     Two  addi- 
tional stokers  have  been  recommended  by  the  superintendent  of  ma- 


JAMES  B.  SCOTT 


225 


chinery,  and  will  probably  be  added  in  the  near  future,  making  a 
total  station  operating  force  of  fourteen  men.  Of  these  an  engineer 
and  stoker  are  on  active  duty  at  all  times,  with  a  four-hour  watch. 
Immediately  upon  the  receipt  of  an  alarm  all  hands  report  on  the 
operating  floor.  As  a  pressure  of  150  Ib.  is  maintained  during  the 
standby  period,  orders  have  been  issued  that  in  the  event  of  the 
pumps  automatically  speeding  up  without  an  alarm,  the  plant  shall 
be  shut  down  immediately.  This  course  is  taken  to  avoid  water 
damage,  should  a  break  occur.  Up  to  this  time  no  occasion  has  arisen 
to  require  the  execution  of  this  order,  however. 

TESTS 
97     Opening  Demonstration.     The  system  was  formally  placed  in 


FIG.  21     CURVE  OF  WATER  PRESSURE  DURING  UNDERWRITERS'  TESTS 

operation  on  May  20,  1912,  with  a  public  demonstration  on  the  Court 
House  Plaza.  At  first  twenty-four  1%-in.  streams  were  used  from 
single  hose  lines  held  by  tripods.  Later  seven  2%-in.  streams  were 
thrown,  from  monitor  nozzles  on  the  wagons.  About  13,000  gal.  per 
min.  were  delivered. 

98     Underwriters'  Tests.    A  readiness  test  was  made  June  7,  -read- 
ings being  taken  by  a  stop-watch. 


226 


BALTIMORE  HIGH-PRESSURE  FIRE  SERVICE 


4.30.00  a.m. 
stoker  on 

4.31.00  a.m. 
and  three 
quarters. 

4.31.15  a.m. 
from  150 

4.33.00  a.m. 
on  to  two 
nozzle. 


Fire  alarm  box  pulled;  one  engineer  and  one 
duty  at  station. 

Chief  engineer  with  four  additional  engineers 
additional  stokers  had  responded  from  sleeping 

Two  large  pumps  started  up,  pressure  increased 
to  190  Ib. 

Pressure   280  Ib.   Hose  company  turned  water 
3-in.  hose  lines  siamesed  into  one  S-in.  monitor 


FIG.  22    CURVE  OF  STEAM  PRESSURE  DURING  UNDERWRITERS'  TESTS 

4.34.00  a.m.     Discharge  was  1050  gal.  per  min. 
4.37.40  a.m.     Two  additional  2%-in.  nozzles  in  service,  total 
discharge  4000  gal.  per  min. 

99  A  second  company  was  then  ordered  into  service  at  another 
point,  with  three  2%-in.  nozzles,  bringing  the  total  discharge  up  to 
7100  gal.  per  min.     See  water  and  steam  charts  from  Bristol  gage  at 
station  (Figs.  21  and  >22). 

100  A  general  performance  test  was  made  June  7,  from  9.45  to 
10.15  a.m.   (see  Bristol  charts).     Pumps  were  started  and  stopped, 
and  hydrants  were  opened  and  closed  as  rapidly  as  possible  to  test 


JAMES  B.  SCOTT 


227 


228  BALTIMORE  HIGH-PRESSURE  FIRE  SERVICE 

the  ability  of  the  pumps  and  governors  to  take  care  of  abnormal 
operating  conditions. 

101  Individual  pump  tests  were  made  the  same  date,  from  10.15 
to  10.45  a.m.,  with  the  following  results : 

Steam  at  throttle,  Ib 146 

Water  pressure,  discharge,  Ib 199 

Water  pressure,  injection,  Ib 41 

Water  pressure,  net,  Ib 158 

Revolutions  per  minute 55 

Discharge,  gal.  per  min 4592 

102  A  general  capacity  test  was  made  10.45  to  1.1.40  a.m.,  with 
the  following  results  (three  pumps  in  service)  : 

Steam  at  throttle  (average),  Ib 145 

Water,  discharge,  Ib 240 

Water,  injection , ? 

Water,  net ? 

Discharge,  gal.  per  min 12,770 

103  During  the  latter  test  six  2y2-in.  nozzles  and  six  2-in.  nozzles 
were  in  use,  discharging  into  the  harbor  (see  Fig.  23). 

RESULTS  OF  OPERATION 

104  The  department  chief  is  enthusiastic  over  the  efficiency  of 
the  entire  system  as  a  modern  fire  fighting  equipment.     He  makes 
the  statement  that  during  the   two   months   which   it  has   been   in 
operation,    three   bad   incipient   fires   have    been   literally   "drowned 
out"  by  the  system.     The  probable   losses   from   these   fires,   under 
former  conditions,  would  more  than  have  equalled  the  entire  cost  of 
the  high-pressure  service.     By  the  time  the  department  arrived  on 
the  scene  at  one  fire,  the  smoke  was  so  dense  that  from  the  middle  of 
the  street  it  was  impossible  to  locate  any  window  or  door  openings 
in  the  building.     Three  2%-in.  monitor  streams  were  blindly  turned 
on  the  building.     The  water  reached  the  fire,  but  not  through  windows 
or  doors.     When  the  smoke  had  cleared  away,  three  holes  were  dis- 
covered in  the  18-in.  brick  walls,  bored  straight  through  the  masonry 
by  the  high-pressure  streams. 

105  The  engineers  of  the  National  Board  of  Fire  Underwriters, 
after  a  thorough  test  and  a  special  search  for  weak  points,  reported 
as  follows : 

The  distributing  system  has  been  installed  for  two  years  and  shows  no  signs  of 
deterioration.  The  slight  leakage,  absence  of  electrolytic  action  and  total  free- 
dom from  breaks  or  other  troubles  appear  to  justify  the  departure  from  the 
usual  design  of  such  systems.  .  .  .  The  valve  and  hydrant  distribution  is 


JAMES  B.  SCOTT  229 

excellent,  and  the  pipe  sizes  and  gridironing  are  sufficient  to  enable  a  good  con- 
centration of  flow  without  serious  loss  of  pressure.  .  .  .  The  separate  hy- 
dra.nt  head  permits  the  use  of  regulator  valves  permanently  attached,  giving 
excellent  control  of  the  pressure  on  hose  lines.  The  hydrant  head  under  test 
showed  sufficiently  low  friction  loss.  .  .  .  The  operation  of  the  pumping 
plant  is  prompt  and  reliable. 

106  As  a  result  of  the  installation  of  the  high-pressure  system, 
the  underwriters  have  announced  a  rebate  of  5  cents  in  the  insurance 
rate  on  all  property  in  the  district  covered.  While  no  exact  sum- 
mary has  been  made  of  the  aggregate  saving  which  will  result  from 
this  reduction,  it  is  roughly  estimated  that  the  amount  will  be  ap- 
proximately $40,000  per  annum,  which  will  be  increased  almost  in 
direct  proportion  with  the  extension  of  the  mains. 

ORGANIZATION 

Construction.  The  executive  head  of  the  project  is  the  Board  of  Fire  Com- 
missioners. To  act  with  the  chief  of  the  department  the  board  appointed  a  con- 
sulting engineer,  D.  B.  Banks,  who  in  collaboration  with  the  writer,  designed  the 
system.  After  the  general  plans  had  been  drawn,  but  before  the  construction 
had  been  begun,  the  board  employed  two  additional  consulting  engineers  to  pass 
upon  the  general  features  of  the  design.  R.  C.  Carpenter  and  Frederick  H. 
Wagner,  chief  engineer  of  Bartlett  &  Hayward  Company,  Baltimore,  were 
chosen,  and  after  a  careful  study  these  engineers  approved  the  general  plans  and 
the  details  as  far  as  completed.  The  architectural  features  of  the  station  were  de- 
signed by  Henry  Brauns,  the  veteran  power  plant  architect  of  Baltimore.  Gen- 
eral supervision  of  the  construction  was  exercised  by  Wm.  McCallister,  Jr., 
assistant  to  the  consulting  engineer.  Before  the  construction  work  was  com- 
pleted, the  department  chief,  George  W.  Horton,  was  retired,  and  the  deputy 
chief,  August  Emerich;  was  promoted  to  the  head  of  the  department. 

Contracts  for  the  various  elements  of  the  system  were  awarded  to  the  following 
builders  and  contractors: 

Automobile  hose  wagons  to  the  Mack  Manufacturing  Company. 

The  portable  hydrant  heads  and  regulators,  and  the  main  pump  governors  to 
the  Ross  Valve  Manufacturing  Company,  of  Troy,  N.  Y. 

The  hydrants  and  high  pressure  water  pipe  lines  to  the  Pittsburgh  Valve 
Foundry  &  Construction  Company  of  Pittsburgh.  Many  of  the  working  details 
of  the  system  were  designed  by  J.  Roy  Tanner,  chief  engineer,  and  Charles 
Fitzgerald,  superintendent  of  construction  for  the  contractor.  A  subcontract 
for  the  supervision  of  the  trenching  was  awarded  by  the  general  pipe  contractor 
to  E.  Saxton,  of  Washington,  D.  C.,  one  of  the  most  experienced  contractors  in 
the  vicinity  on  subsurface  structures  in  city  streets. 

Pumps  to  the  Allis-Chalmers  Company,  of  Milwaukee,  although  this  concern 
was  not  the  lowest  bidder.  A  subcontract  for  the  1000-gal.  direct  acting  pump 
and  the  boiler  feed  pumps  was  awarded  to  the  Epping  Carpenter  Company,  of 
Pittsburgh. 


230  BALTIMORE  HIGH-PRESSURE  FIRE  SERVICE 

Boilers  to  the  Edge  Moor  Iron  Company  of  Wilmington,  Del.  A  subcontract 
for  the  stokers,  blowers  and  regulators  was  awarded  to  the  Underfeed  Stoker 
Company  of  America,  Chicago. 

The  steam  and  auxiliary  water  piping  in  the  pumping  station  to  the  Crook- 
Kries  Company,  of  Baltimore. 

The  station  building  and  harbot  intake  to  the  B.  F.  Bennet  Building  Company, 
of  Baltimore. 

The  signal  system  was  installed  by  the  department  force. 


No.  1393  c 

ALLOWABLE  HEIGHTS  AND  AREAS  FOR 
FACTORY  BUILDINGS 

BY  IRA  H.  WOOLSON,  NEW  YORK 
Member  of  the  Society 

In  the  design  of  factory  buildings,  one  of  the  vital  features  tend- 
ing to  control  the  spread  of  fire  is  a  judicious  limitation  of  height 
and  area.  It  is  self-evident  that  whatever  restricts  a  fire  reduces  the 
life  hazard.  Owing  to  the  supreme  importance  of  these  two  subjects, 
a  person  contemplating  the  erection  of  a  building  of  this  class  should 
give  careful  consideration  to  the  history  of  fires  in  such  buildings,  and 
the  experience  gained  in  fighting  them.  The  question  is  more  acute 
in  this  class  of  buildings  than  in  any  other  because  of  the  fire  hazard 
which  exists  in  them,  and  the  economic  advantages  due  to  reduced 
costs  in  construction  and  supervision,  when  several  large  areas  are 
housed  under  a  single  roof.  Just  where  to  draw  the  line  so  as  to 
produce  reasonable  safety  without  prejudice  to  building  investments 
is  the  problem. 

2  Factory  buildings  of  excessive  heights  or  areas  have  long  been 
recognized  by  underwriting  organizations  as  a  grave  danger  to  life 
and  property,  owing  to  the  difficulty  of  controlling  fires  in  them. 
They  have  for  years  urged  limitations  which  have  been  freely  ignored 
by  ambitious  architects  and  factory  owners,  because  the  suggested 
restrictions  were  considered  unreasonably  drastic.    The  evidence  pro- 
duced in  this  paper  strongly  supports  the  limitations  which  were 
advocated. 

3  It  is  logical  to  assume  that  the  men  best  fitted  to  determine 
safe  limits  of  heights  and  areas  are  the  men  who  have  made  a  life 
work  of  combating  fires  under  all  conditions  of  weather  and  hazard. 
With  this  idea  in  mind,  the  writer  communicated  with  all  the  fire 
marshals  and  fire  chiefs  in  the  United  States  representing  cities  of 
over  20,000  population.     A  set  of  eight  questions  and  a  letter  of 
explanation  were  sent  to  each.     Fire  chiefs  as  a  class  are  not  good 
technical  correspondents,  therefore  it  was  not  surprising  that  only 


Presented  at  the  Spring  Meeting,  Baltimore  1913,  of  THE  AMERICAN  SO- 
CIETY OF  MECHANICAL  ENGINEERS. 

231 


232  HEIGHTS  AND  AREAS  FOR  FACTORY  BUILDINGS 

one-third  of  the  men  addressed  responded  to  the  appeal.  However, 
replies  were  received  from  117  representative  cities  well  distributed 
as  to  size  and  geographical  location.  These  have  been  summarized  and 
form  the  basis  of  this  paper.  A  few  of  the  replies  indicated  a  mis- 
understanding of  the  questions,  and  these  were  discarded.  The 
questions  were  as  follows: 

1  What  should  be  the  greatest  height  allowed  for  manufacturing  or 

warehouse  buildings  without  sprinkler  equipment? 

Brick  and  joist  construction Height  in  ft. or  No.  of  Stories — 

Fireproof  construction Height  in  ft. or  No.  of  Stories 

2  Take  the  same  question  as  No.  1,  but  assume  the  buildings  to  be  fully 

equipped  with  automatic  sprinklers.     What  height  would  you  ap- 
prove ? 

Brick  and  joist  construction Height  in  ft. or  No.  of  Stories 

Fireproof  construction Height  in  ft. or  No.  of  Stories 

3  What  should  be  the  greatest  floor  area  allowed  in  the  same  class  of 

buildings  without  sprinkler  equipment? 

Brick  and  joist  construction  Area  in  sq.  ft. or  Width ft  Length ft. 

Fireproof  construction Area  in  sq.  ft. or  Width ft.  Length ft. 

4  If  the  same  buildings  were  fully  equipped  with  automatic  sprinklers 

what  area  would  you  approve? 

Brick  and  joist  construction  Area  in  sq.  ft. or  Width ft.  Length ft. 

Fireproof  construction    Area  in  sq.  ft. or  Width ft.  Length ft. 

4  Each  building  was  assumed  as  a  good  one  of  its  class,  with 
enclosed  stairways  and  elevator  shafts;  and  the  chiefs  were  requested 
to  base  their  answers  upon  experience  in  fighting  fires  in  the  class 
of  buildings  described,  and  to  assume  restrictions  which  would  afford 
a  reasonable  chance  of  controlling  a  fire  on  any  floor. 

TABLE  1      GENERAL  AVERAGE  OF  99  TO  111  REPLIES  RECEIVED  FROM  ALL 
CLASSES  OF  CITIES1 

Stories  in  Area  between  Fire 

Type  of  Building                                Height  Walls  in  Sq.  Ft. 

Non-fireproof,  not  sprinklered 3.1  6,300 

Fireproof,  not  sprinklered 4.9  12,300 

Non-fireproof,   sprinklered 4.6  12,800 

Fireproof,  sprinklered 7.0  27,100 

Average  story  height  was  12  to  13  ft. 

5  Naturally,   and  quite  properly,   the   replies   reflect   the  local 
conditions,  such  as  the  efficiency  of  the  fire  department,  the  water 
pressure,  the  combustibility  of  the  goods  being  manufactured,  the 

'The  variation  in  the  number  of  replies  (averaged)  resulted  from  some  in- 
complete answers. 


IRA  H.  WOOLSON  233 

number  of  sprinkler  equipments  in  service,  and  the  degree  of  con- 
gestion among  the  buildings.  However,  all  conditions  were  repre- 
sented, and  the  summary  of  so  large  a  number  of  opinions  should 
indicate  fairly  well  the  average  condition  throughout  the  country. 
(See  Table  1.) 

6  The  answers  regarding  allowable  heights  were  much  more 
uniform  than  those  relative  to  area.    It  is  significant  that  83  per  cent 
of  the  replies  would  limit  the  height  of  a  fireproof  sprinklered  factory 
building  to  less  than  ten  stories.    The  opinions  in  reference  to  height 
of  the  other  classes  of  buildings  were  exceedingly  uniform,  and  con- 
sistently low. 

7  Replies  as  to  permissible  areas  in  sprinklered  buildings  were 
widely  divergent,  but  for  the  unsprinklered  classes  they  were  more 
uniform  than  would  naturally  be   expected  considering  the  great 
diversity  of  conditions  under  which  they  were  prepared. 

8  It  is  evident  from  the  figures  given,  that  the  fire  chiefs  have  no 
settled  policy  among  themselves  as  to  the  credit  that  should  be  given 
to  an  automatic  sprinkler  equipment  as  a  fire  extinguishing  device. 
A  few  enthusiasts  would  permit  unlimited  area  in  a  sprinklered 
building,  while  on  the  other  hand  a  considerable  number  would  give 
very  little  or  no  increase,  when  sprinklers  are  installed.     Two  chiefs 
stated  that  their  unfortunate  experiences  with  sprinklers  had  caused 
them  to  lose  faith  in  their  reliability.    As  a  whole,  however,  they  are 
strongly  in  favor  of  sprinklers  and  are  inclined  to  permit  over- 
generous  areas  in  buildings  so  equipped. 

9  In  order  that  the  replies  may  be  intelligently  interpreted  they 
have  been  separated  into  three  groups,   Tables  2,  3,  4,   according 
to  size  of  the  city  represented,  and  each  group  has  been  analyzed  to 
show  the  character  of  the  answers  given  to  each  question. 

10  In  the  cases  referred  to  by  an  asterisk,  where  no  limits  to 
areas  were  given,  they  were  not  included  in  the  averages,  but  were 
counted  in  the  columns  giving  the  number  of  answers  above  the 
average.    In  each  group  it  will  be  noted  that  about  the  same  number 
of  men  gave  high  answers  to  all  questions,  the  proportion  being  one- 
quarter  to  one-half  of  the  number  in  the  group.   The  uniformity  of 
height  limits,  and  the  lack  of  it  in  the  area  limits,  is  very  apparent 
in  all  groups.    It  will  be  noted  that  the  largest  area  values  are  given 
in  Groups  I  and  II,  comprising  the  smaller  cities.    This  is  significant, 
and  needs  explanation. 

1.1     Occasionally  the  fire  chief  of  a  small  city  has  experience  which 
would  abundantly  qualify  him  to  estimate  properly  the  merits  of  fire- 


234 


HEIGHTS  AND  AREAS  FOR  FACTORY  BUILDINGS 


proof  construction  and  sprinkler  equipments ;  more  often,  however,  his 
city  has  meager  protection  of  this  kind,  and  consequently  he  has  little 

TABLE  2     GROUP  I     SUMMARY  OF  ANSWERS  FROM  52  CITIES  WITH  A  POPULA- 
TION OF  20,000  TO  50,000 


Type  of  Building 

Stories  in  Height 

Answers 
above 
Average 

Area  in  Square  Feet 

Answers 
above 
Average 

15 
15 

Average 

Max. 

Min. 

Average 

Max. 

Min. 

Non-fireproof,     not     sprink- 
lered  

2.8 

6 

1 

13 

6,000 

20,000 

1,150 

Fireproof,  not  sprinklered  .  .  . 

4.4 

10 

2 

24 

12,600 

60,000 

1,150 

Non-fireproof,  sprinklered.  .  . 

4.1 

8 

2 

17 

12,300 

*60,000 

3,000 

17 

Fireproof,  sprinklered  

6.3 

12 

3 

18 

27,300 

*180,000 

5,000 

20 

*  Four  votes  received  in  favor  of  "no  limit  to  area"  in  this  class. 


TABLE  3     GROUP  II     SUMMARY  OF  ANSWERS  FROM  23  CITIES  WITH  A  POPULA- 
TION OF  50,000  TO  100,000 


Type  of  Building 

Stories  in  Height 

Answers 
above 
Average 

Area  in  Square  Feet 

Answers 
above 
Average 

Average 

Max. 

Min. 

Average 

Max 

Min. 

Non-fireproof,     not     sprink- 
lered   

3.2 

6 

1 

8 

8,300 

40,000 

2,500 

5 

Fireproof,  not  sprinklered  .  .  . 

5.2 

10 

1 

6 

14,800 

60,000 

2,400 

4 

Non-fireproof,  sprinklered  .  .  . 

4.8 

10 

3 

5 

16,300 

75,000 

1,500 

5 

Fireproof,  sprinklered  

7.7         20 

4 

5 

36,300 

200,000 

4,000 

5 

TABLE  4     GROUP  III     SUMMARY  OF  ANSWERS  FROM  36  CITIES  WITH  A  POPULA- 
TION OF  100,000  AND  OVER 


Type  of  Building 

Stories  in  Height 

Answers 
above 
Average 

Area  in  Square  Feet 

Answers 
above 
Average 

Average 

Max. 

Min. 

Average 

Max. 

Min. 

Non-fireproof,     not     sprink- 
lered  

3.5 

7 

1 

17 

5,400 

10,000 

900 

15 

Fireproof,  not  sprinklered  .  .  . 

5.3 

9 

2 

18 

9,800 

22,500 

2,400 

10 

Non-fireproof,  sprinklered.  .  . 

5.0 

10 

3 

15 

11,300 

22,500 

900 

13 

Fireproof,  sprinklered  

7.5 

12 

4 

16 

19,400 

*80,000 

2,500 

9 

*  Two  votes  received  in  favor  of  "no  limit  to  area"  in  this  class. 


opportunity  to  judge  of  their  efficiency,  and  it  is  not  strange  that  he 
should  be  a  bit  extravagant  in  the  credit  he  would  give  them. 


IRA  H.  WOOLSON  235 

12  The  most  rigid  restrictions  on  area  are  found  in  Group  III 
embracing  the  large  cities.     As  fireproof  construction  and  sprinkler 
equipments  are  common  in  most  of  our  large  cities,  it  is  reasonable 
to  assume  that  the  fire  chiefs  of  such  cities  would  have  had  more  ex- 
perience with  such  methods  of  protection,  and  be  better  able  to  decide 
what  increase  should  be  given  in  the  size  of  a  building  when  such  pro- 
tection  is   provided,   than   their   less   experienced   fellow   officers   in 
smaller  towns.     It  is  thought  quite  proper  to  assume  their  figures 
are  more  nearly  correct  and  should  be  given  the  most  weight. 

13  Significant  evidence  in  support  of  this  argument  is  found 
in  the  fact  that  four  chiefs  who  give  no  limit  to  areas  in  non-fireproof 

TABLE  5      ALLOWABLE  HEIGHTS  AND  AREAS  IN  FACTORY  BUILD-INGS 

Stories  in  Area  between  Fire 

Type  of  Building                                    Height  Walls  in  Sq.  Ft. 

Brick  and  joist  construction,  not  sprinklered.     3  6,000 

Fireproof  construction,  not  sprinklered 5  10,000 

Brick  and  joist  construction,  sprinklered 5  13,000 

Fireproof  construction,  sprinklered 8  20,000 

and  fireproof  sprinklered  buildings  are  located  in  cities  having  a 
population  of  less  than  50,000  in  which  there  are  few  fireproof 
factory  buildings  or  sprinkler  equipments.  On  the  other  hand  only 
two  chiefs,  in  cities  over  100,000  population,  suggest  a  "no  limit 
area"  in  a  fireproof  sprinklered  building,  and  none  approves  such 
areas  for  non-fireproof  buildings. 

TABLE  6     AREAS  IN  FACTORY  BUILDINGS 

AVERAGE  OF  THE  REPLIES  OP  50  FIRE  CHIEFS  SELECTED  FROM  117,  THE  TOTAL  NUMBER 

RECEIVED  AS  BEST  QUALIFIED  BY  TRAINING  AND  EXPERIENCE  TO 

PASS  JUDGMENT  ON  THE  QUESTIONS  INVOLVED 


TYPE  OF  BUILDING 

STORIES  IN  HEIGHT 

AREA  BETWEEN  FIRE 
WALLS  IN  SQ.  FT. 

Brick  and  joist  construction,  not  sprinklered 

3.2 

5,200 

Fireproof  construction,  not  sprinklered 

5.3 

9,300 

Brick  and  joist  construction,  sprinklered 

4.8 

10,500 

Fireproof  construction,  sprinklered 

7.5 

21,600 

14  With  these  thoughts  in  view,  Table  1  has  been  changed 
somewhat  to  be  more  in  accord  with  the  weight  of  evidence.  It  is 
believed,  therefore,  that  Table  5  represents  more  correctly  the  con- 
sensus of  opinion  among  the  fire  chiefs  of  the  country  best  qualified 


236  HEIGHTS  AND  AREAS  FOR  FACTORY  BUILDINGS 

to  judge  as  to  what  should  be  the  proper  limits  of  height  and  area 
for  factory  buildings. 

15  These  values  might  be  increased  somewhat  under  the  influence 
of  especially  favorable  local  conditions,  as  previously  explained,  but 
the  writer  submits  that  as  they  represent  the  average  deliberate  judg- 
ment of  such  a  large  body  of  men,  so  well  qualified  to  estimate  the 
hazard  which  the  values  involve,  they  should  be  given  careful  con- 
sideration, and  should  be  increased  only  with  the  utmost  caution. 

In  selecting  the  above  replies,  attention  was  specifically  given 
not  only  to  the  personality  of  the  fire  chief,  but  also  to  the  character 
and  number  of  factory  buildings  in  his  city,  and  the  probability  of 
his  having  experience  with  both  fireproof  construction  and  sprinkler 
equipment. 

The  chiefs  selected  were  distributed  according  to  size  of  cities  as 
follows:  32  from  cities  with  a  population  of  over  100,000;  14  from 
cities  with  a  population  of  50,000  to  100,000;  4  from  cities  with  a 
population  of  20,000  to  50,000. 

It  will  be  noted  that  the  figures  in  this  table  of  actual  averages 
compare  very  closely  with  those  given  in  Table  5  which  was  com- 
piled by  a  somewhat  arbitrary  method  in  an  effort  to  bring  out  the 
same  facts. 

EXTRACTS  FROM  FIRE  CHIEFS'  LETTERS 

16  The  following  extracts  from  letters  received  from  different 
fire  chiefs  in  connection  with  this  investigation  may  be  of  interest  as 
indicating  their  attitude  of  mind  in  relation  to  the  questions  asked : 

' '  In  my  opinion,  from  a  fire-fighting  standpoint,  no  building  should  be  built 
over  eight  stories. ' ' 

1 '  In  our  city  there  is  room  to  grow  on  the  ground  without  building  high  in 
the  air.  It  is  almost  impossible  for  a  public  fire  department  to  fight  a  fire 
from  the  outside  above  75  ft." 

' '  The  figures  given  mean  that  every  66  ft.  by  66  ft.  should  have  a  brick  wall 
through  length  of  building  with  Underwriters'  doors,  same  to  be  double.  As 
for  width,  in  no  case  over  66  ft.  wide;  with  solid  wall,  same  to  reach  above 
roof  at  least  6  ft.  Build  on  ground  not  in  air." 

( '  A  building  8  or  10  stories  high,  out  in  the  open  where  it  can  be  attacked 
from  all  sides  should  be  handled  very  readily  by  a  modern  equipped  fire  de- 
partment. ' ' 

"I  think  that  a  factory  should  never  be  more  than  four  stories  high.  I 
almost  feel  that  there  is  no  such  thing  as  fireproof  construction  from  my  own 
experience.  I  know  that  it  is  possible  to  store  enough  material  in  any  building 
to  burn  it.  I  am  very  much  in  favor  of  dividing  rooms  in  factories  with  fire- 
resisting  walls,  provided  with  automatic  fire  doors." 

' l  While  fireproof  construction  is  the  best,  it  is  the  contents  placed  therein 
that  is  the  hazard  to  life  and  property.  Buildings  should  not  be  constructed 


IEA  H.  WOOLSON  237 

to  a  greater  height  than  can  be  reached  by  fire  department  ladders;  85  ft.  to 
upper  windows." 

' '  In  my  opinion  no  warehouse  building  ought  to  be  over  one  story  in  height. 
In  regard  to  manufacturing  buildings,  I  will  say  that  I  do  not  approve  of  any 
of  these  buildings  being  over  three  stories  in  height.  If  they  want  room,  let 
them  build  in  length  and  not  so  high;  that  is  just  what  makes  such  bad  fires. 
These  buildings  have  all  kinds  of  combustible  material  in  them  and  they  are 
sure  to  jump  to  another  building  if  they  are  four  or  five  stories  in  height." 

"It  is  my  opinion  that  all  buildings  for  manufacturing  and  warehouses 
should  be  sprinklered,  and  not  built  higher  than  what  the  water  supply  will 
furnish  and  cover." 

"Do  not  think  any  fire  department  can  successfully  fight  a  large  fire  over 
six  stories  high,  and  ten  stories  allowed  only  when  there  are  two  sources  of  wa- 
ter supply  with  good  pressure." 

' '  Area  of  sprinklered  and  unsprinklered  buildings  should  be  about  the  same, 
on  account  of  increase  in  height  allowed  for  fireproof  buildings. ' ' 

"All  buildings  of  character  named  should  be  sprinklered." 

' '  Joisted  brick  construction  should  not  be  allowed  without  sprinklers. ' ' 

' '  I  think  a  good  sprinkler  system  is  one  of  the  best  fire  preventions  that  has 
been  invented  in  a  great  many  years,  and  if  kept  up  properly,  it  is  pretty  hard 
for  fires  to  get  away." 

"  If  I  had  my  way  I  would  not  allow  any  manufacturing  plant  to  do  busi- 
ness until  it  were  properly  sprinklered.  It  does  things  when  they  should  be 
done." 

' '  My  experience  with  the  28  factories  in  this  city  has  been  that  the  sprinkler 
systems  are  out  of  order  much  of  the  time.  Not  looked  after  properly." 

' '  This  department  has  had  no  unfortunate  experience  with  the  sprinkler  sys- 
tem, but,  I  do  not  feel  inclined  to  depend  upon  them. ' ' 

"The  reason  for  not  showing  more  favor  to  sprinklered  risks,  is  because 
our  experience  with  sprinkler  systems  in  this  city  has  shown  them  to  be  unsatis- 
factory, and  not  to  be  depended  on." 

1 '  Stairs  should  be  of  steel  without  any  wood  sides ;  if  any  wood  in  the  con- 
struction then  there  should  be  sprinklers.  Should  be  sprinklers  in  all  elevators 
even  if  they  are  enclosed,  for  an  elevator  is  a  bad  air  shaft.  Brick  factories 
cut  up  with  wooden  partitions  are  generally  hard  fires  to  fight. ' ' 

"  I  do  not  approve  of  small  rooms  in  factories,  they  make  it  very  hard  for 
a  fireman  to  fight  his  way  through  smoke  trying  to  find  a  fire  when  a  building 
of  this  kind  is  partitioned  off  so  much." 

' '  In  considering  the  limiting  of  height  and  area  of  a  building,  the  question 
of  accessibility  should  play  an  important  part." 


No.  1393  d 

THE  PROTECTION  OF  MAIN  BELT  DRIVES 
WITH  FIRE  RETARD  ANT  PARTITIONS 

BY  C.  H.  SMITH/  BOSTON,  MASS. 
Non-Member 

The  importance  of  safeguarding  stairways  by  placing  them  in 
towers  well  cut  off  from  the  remainder  of  the  building  and  of  pro- 
tecting the  openings  made  by  elevators  through  the  floors  has  long 
been  recognized.  Today  more  than  formerly,  these  features  are  taken 
care  of  in  the  design  of  manufacturing  buildings,  including  also  well 
arranged  towers  for  the  main  belts  or  ropes  where  this  method  of 
driving  is  employed.  Fig.  1  shows  how  these  features  may  be  taken 
care  of  in  a  textile  mill. 

2  The  following  remarks  apply  more  particularly  to  the  older 
manufacturing  buildings  and  to  those  of  more  recent  construction 
where  the  best  principles  of  design  of  stair  and  elevator  towers  and 
belt  and  ropeways  have  not  been  followed.    Neglect  to  safeguard  ver- 
tical openings  through  floors  has  resulted  in  serious  loss  of  life  among 
occupants  of  the  building,  who  found  themselves  cut  off  from  their 
accustomed  exits  by  the  rapid  spread  of  fire  up  through  such  unpro- 
tected openings. 

3  In  mills  insured  with  the  Mutual  companies  stairs  and  elevators 
have  generally  been  well  arranged,  and  the  fire  protective  devices  such 
as  automatic  sprinkler  systems,  etc.,  have  shown  their  value  not  only 
in  reducing  the  loss  of  property  by  fire  to  a  minimum,  but  also  it 
has  been  demonstrated  that  approved  construction,  high  standards  of 
general  order  and  neatness  and  efficient  fire  protection  works  as  well 
to  safeguard  the  lives  of  operatives  employed. 

4  .At  the  present  time  there  are  approximately  1,500,000  people 
employed  in  the  2800  industrial  works  insured  with  the  Mutual  com- 
panies, located  in  29  states  of  the  Union  and  Canada.     .Since  the 
inception  of  the  system  in  1835,  there  have  been  but  32  deaths  caused 
directly  by  fires  in  these  properties  and  21  were  in  a  fire  in  an  un- 

^ngineer  and  Special  Inspector,  Associated   Factory  Mutual  Fire  Insur- 
ance Companies,  31  Milk  Street. 

Presented  at  the  Spring  Meeting,  Baltimore  1913,  of  THE  AMERICAN  SO- 
CIETY OF  MECHANICAL  ENGINEERS. 

239 


240 


PROTECTION  OF  MAIN  BELT  DRIVES 


sprinkler ed  mill  in  1876  before  sprinklers  were  in  general  use.  This 
would  indicate  that  under  present  conditions,  the  loss  of  life  would 
average  less  than  1  per  year  per  1,000,000. 

5  Of  the  total  of  32  lives  lost,  poorly  constructed  beltways  which 
allowed  the  rapid  spread  of  smoke  and  flame  were  to  a  large  extent 
responsible  for  the  deaths  of  25  persons.  The  need  of  safeguarding 
the  vertical  openings  through  floors  around  the  main  driving  belts 


Stair     Dust    Elevator       Belf  or  Rope  Tower 
Toiler     Chy.   &  Passage 

SECTION 


Engine  House  Boiler  House 


PLAN 

PIG.  1     BELT,  STAIRWAY  AND  ELEVATOR  TOWERS 

had  been  less  fully  appreciated.  Conditions  at  these  drives  were  ag- 
gravated moreover,  because  it  was  the  general  custom  to  enclose  the 
belts  with  boxes  of  wood,  which  in  some  cases  were  about  head  high 
and  in  others  extended  to  the  ceiling.  The  boxes  tended  to  become  oil 
soaked  and  to  accumulate  lint.  A  fire  once  starting  at  or  near  them 
would  rapidly  make  headway,  being  carried  by  the  natural  draft  up 
through  the  mill.  Such  a  fire  would  also  be  more  or  less  sheltered 
from  the  action  of  the  sprinklers  in  the  room. 

6     The  recurrence  of  several  large  property  losses  from  this  source 
led  to  consideration  of  this  matter  and  measures  were  taken  which 


C.  H.  SMITH 


241 


have  to  a  great  extent  eliminated  the  open  beltway  hazard  from  Mutual 
risks.  In  the  experience  of  these  companies  there  have  been  about  20 
fires  occurring  in  the  vicinity  of  main  drives  in  which  the  open  belt- 
way  was  an  important  factor  in  the  spread  of  the  fire.  These  20  fires 
resulted  in  a  total  loss  of  $2,72-1,635,  an  average  of  $136,0i82  per  fire. 
Some  of  the  larger  of  these  losses  occurred  in  the  days  before  sprinkler 
protection  was  as  complete  as  now,  but  the  statistics  showed  that  even 
with  complete  protection  the  open  beltway  was  a  serious  hazard. 


Ring   Spinning 
(driven   from    below) 


FIG.  2     SECTION  SHOWING  BELTS  AND  WOODEN  BOXING  BEFORE  FIRE  OF 
SEPTEMBER  15,  1907 


7  The  last  bad  fire  from  this  source  occurred  September  15,  1907, 
at  a  cotton  manufacturing  establishment  in  Fall  River.     This  is  a 
stone  mill,  339  ft.  long,  74  ft.  wide  and  five  stories  and  basement  in 
height  with  a  -1-story  wing,  94  ft.  long  and  65  ft.  wide,  projecting 
from  the  rear  at  the  center  of  the  mill.    The  engine  room  was  located 
in  the  first  story  of  this  wing.    The  belts  were  boxed  with  wood  and 
most  of  these  were  cut  off  head  high  in  the  several  stories'.     Fig.  .2 
shows  the  general  arrangement  of  the  drive. 

8  Sunday  forenoon  a  bearing  in  the  beltway  just  above  the  fly- 
wheel was  being  repaired.    While  the  man  doing  the  work  stated  that 
he  had  no  knowledge  of  anything  that  could  cause  the  fire,  it  is 


242 


PROTECTION  OF  MAIN  BELT  DRIVES 


fffiee-, 


Sections  of  Partition 
Showing  Framing 


Expanded  Me  fa  I 
•-Where  partition  is  continuous  for  more  than  10', 

troduce  as  stiffener  a  Z%  T-bar  upright  fagged 
to  floorfrfei/ing.  If  length  of  parf/tion  is  more 
tfxrn  20,  space  stiffeners  about  10  'apart. 


,-3'u  riveted  to  2'L  with  "rivets. 


'Head  over  bo  I  tend  after 
nut  is  screwed  on  tight. 


*.~2  L's  riveted  together*, 
with  s'rivefs.oountgrs.  I 
heads.Zf'apart. 


''Na&  Diamond  Lath  Exp.Meial, 
wired  to  u's  at  least  every  6*. 


^/y  flfoc?/-  opening  exceeds  5  'use 
tor  jambs  andZ-Z^L  's  tor  transom  bar. 


,  %" Removable  L  allaround 
\frametoholdinwired 


'A'-Recess  for  Bearing 


1'u 

lronframe 
Section  F-F 


Wired  Glass- 
Section  B-B 

SPECIFICATIONS  FOR  PLASTER 
Scratch  Coat  (To  be  puton  first): 
";'s  Portland  Cement.  JE  parts  Sane/,  I  part 
Hyd  rated  Lime.  suffitientamounfHair  fomake 
mortar  work  properly.  <Shou/dbe  mixed  in  sma// 
batches.  No  material  thathas  been  mixed  with 
water  longer  than  30  min.  shou/a"  be  used. 

Finish  Coat 

(One  caat  inside  &one  outside,  trowel  led  smooth) 
I  part  Portland  Cement,  tyopart&ind,  '//o 
part  Hyd  rated  Lime  Paste. 


WiredGlass 


1  Stove  Bolts  with  Washers' 

Window  (About 3x5'; 

Framing 


FIG.  3    DETAILS  OP  CONSTRUCTION  FOR  FIRE  EETARDANT  BELT  ENCLOSURES 


C.  H.  SMITH  243 

probable  that  its  origin  was  connected  with  his  work.  After  com- 
pleting the  job  he  left  the  locality.  On  returning  10  minutes  later,  he 
saw  fire  just  below  where  he  had  been  at  work,  and  gave  the  alarm. 

9  The  fire  passed  up  through  the  wooden  belt  boxing  into  all 
stories  as  far  as  the  fourth  floor  where  the  drive  terminated.     The  mill 
filled  with  heat  and  smoke  so  rapidly  that  in  5  minutes  no  one  could 
enter  the  rooms.     This  was  in  spite  of  650  sprinklers  which  opened, 
but  in  justice  to  the  sprinkler  equipment,  it  should  be  stated  that  the 
water  pressure  at  this  mill  was  weak.     A  section  about  50  ft.  wide 
was  badly  burned  on  each  side  of  the  main  drive  up  through  the  mill. 

10  After  this  fire  plans  were  worked  out  to  enclose  the  main 
drives  with  partitions  of  a  fire  retardant  character,  so  as  to  approximate 
the  standard  belt  tower  with  brick  walls,   such   as   are  found  in 
many  mills  of  modern  design. 

11  The  limitations  of  cost,  available  space,  etc.,  which  prevail  in 
many  places  where  the  belt  tower  is  not  a  part  of  the  original  design, 
make  necessary  special  construction  such  as  was  adopted  in  this  case, 
and  has  been  successfully  used  in  many  others  of  the  older  mills. 

12  The  plan  provided  for  inclosing  the  main  drives  with  parti- 
tions of  expanded  metal  and  cement  construction  from  2  in.  to  2~y2  in. 
thick  depending  on  the  story  heights.     A  framework  is  constructed 
of  expanded  metal  wired  to  1  in.  or  1%  in.  channel  iron  studs  spaced 
12. in.  apart,  and  secured  to  the  floor  and  ceiling.     Longitudinal 
stiffeners  of  the  same  material  as  the  studs  are  used.    Where  necessary, 
as  in  the  case  of  a  continuous  partition  of  more  than  10  ft.,  additional 
stiffness  is  secured  by  providing  2l/2  in.  tee-bar  uprights.     On  the 
frame  so  constructed  portland  cement  mortar  is  applied  by  plastering 
to  make  a  solid  partition,  all  of  the  iron  frame  being  embedded  in 
the  cement  with  the  exception  of  the  door  jambs.     These  partitions, 
being   comparatively   light   in   weight,    could   be   set   up   anywhere 
on  the  heavy  mill  floors  without  the  necessity  of  strengthening  them, 
although  where  possible  it  was  arranged  to  have  the  partitions  come 
over  the  beams.     Although  this  form  of  construction  for  partitions 
has  been  largely  used  and  with  satisfaction,  it  would  be  possible  of 
course  to  employ  some  of  the  special  forms  of  studding  now  on  the 
market  which  combine  the  studs  and  lathing  in  one  sheet  of  metal. 
Details  of  the  construction  used  are  shown  in  Fig.  3. 


244 


PROTECTION  OF  MAIN  BELT  DRIVES 


13  While  in  general  the  enclosures  occupy  only  the  floor  space 
necessary  for   the  main  belts,   it  was  endeavored  to  have  them  as 
roomy  as  conditions  of  machinery  installation  would  permit,  in  order 
to  facilitate  inspection  and  repairs  to  the  main  belts.     Provision  was 
made  for  taking  down  the  lineshafting  without  disturbing  the  body 
of  the  partitions,  usually  by  placing  the  fire  doors  which  gave  access  to 
the  enclosure  under  the  lineshaft,   and   providing  removable   wood 
tin-clad  panels  constructed  like  fire  doors  above  the  latter.    The  main 
bearings  were  generally  left  outside  the  enclosures  and  to  accomplish 
this  the  panels  in  front  of  the  pulleys  were  sometimes  recessed. 

14  It  was  also  the  endeavor  to  arrange  these  enclosures  so  that 
they  would  be  as  well  lighted  as  possible  by  including  in  them  windows 
in  the  side  wall  of  the  building  or  providing  wired  glass  windows  in 


I  Wood 
Plank  Tops 

Plaster  on  Expanded  Metal 
;;';L«3|Galvanized  Iron 


Ring   Spinning 

(driven  from    below) 


HH 


FIG.  4    SECTION  SHOWING  MAIN  DRIVE  AS  NOW  PROTECTED  BY  FIRE  EETARDANT 

ENCLOSURES 


metal  frames  to  admit  light  to  the  beltway  from  the  room.  Fig.  4 
shows  diagrammatically  the  completed  work  at  the  Fall  Eiver  mill, 
and  Figs.  5,  6,  7  and  8  are  photographs  of  belt  enclosures  in  different 
stories.  The  adaptability  of  the  construction  is  evidenced  in  the 
sloping  sides  and  offsets  which  it  was  necessary  to  make  in  many  cases 
on  account  of  crowded  conditions  in  the  vicinity  of  the  main  belts. 
15  While  there  is  no  claim  that  these  partitions  are  as  efficient 


C.  H.  SMITH  245 

in  withstanding  the  action  of  a  severe  fire  as  a  brick  wall  would  be, 
they  are  undoubtedly  effective  in  preventing  the  dangerous  draft  up 
through  an  open  beltway.  In  an  actual  fire  in  one  of  the  mills  where 
this  construction  was  installed  these  enclosures  were  successful  in 
confining  the  fire  to  narrow  limits,  and  undoubtedly  prevented  a  very 
serious  loss. 

16  Stairways.     Where  interior  stairways  are  not  properly  en- 
closed in  brick  towers,  it  is  possible  to  improve  the  conditions  with 
enclosures  of  the  same  type  of  construction  as  employed  in  the  beltway 
work,  although  it  would  be  much  better  where  the  appropriation  can 
be  secured  to  build  a  standard  tower  of  brick  or  concrete,  especially  if 
the  mill  is  of  any  considerable  height.    Placing  the  stairs  and  eleva- 
tors in  towers  projecting  from  the  mill  wall  frequently  results  in  a 
gain  of  valuable  floor  space. 

17  The  type  of  stair  tower  that  has  been  developed  in  the  factory 
buildings  at  Philadelphia  is  deserving  of  more  general  adoption  as  it 
combines  with  its  functions  of  a  stair  tower  that  of  a  fire  escape  in 
the  best  sense.    It  consists  essentially  in  a  tower  separated  from  the 
mill  so  that  access  to  it  can  be  had  from  the  several  floors  of  the  mill 
only  from  an  outside  platform  or  from  a  vestibule  which  is  open  to 
air.    Such  a  tower  can  never  become  filled  with  smoke  from  a  fire  in 
the  mill.     Many  of  the  older  mills  in  other  sections  of  the  country 
have  stair  towers  that  can  be  readily  converted  into  towers  of  the 
Philadelphia  type  by  closing  the  openings  between  the  stair  tower  and 
the  mill  in  the  several  stories  and  arranging  for  an  outside  platform 
in  each  story  communicating  from  the  mill  to  the  tower. 

18  Elevator  Enclosures.    We  have  also  found  the  use  of  expanded 
metal  and  cement  partitions  practicable  for  enclosing  elevator  wells 
that  were  not  properly  protected  in  the  original  construction  of  the 
building,  or  where  they  have  since  been  added.     The  necessary  open- 
ings at  such  elevator  shafts  should  be  closed,  preferably  with  wood 
tin-clad  doors  of  the  type  which  serve  as  safety  gates  as  well.    Where 
space  does  not  permit  of  the  installation  of  such  doors,  rolling  steel 
shutters  arranged  to  be  automatically  operative  by  the  melting  of  a 
fusible  link,  as  well  as  manually,  can  be  used  providing  the  hazards 
of  occupancy  are  not  excessive. 

19  Other  Uses.    The  average  cost  of  partitions  of  the  construc- 
tion advocated  is  from  30  cents  to  33  cents  per  sq.  ft.    These  figures 
are  for  the  work  in  place  and  include  a  contractor's  profit.     These 
partitions  have  been  used  with  superior  results  and  not  greatly  in- 


246 


PROTECTION  OF  MAIN  BELT  DRIVES 


FIG.  5     HARNESS  BOOM,  SECOND  STORY,  DIRECTLY  OVER  FLYWHEEL  SHOWING 
PROTECTION  OF  BELTS  LEAVING  WHEEL 


FIG.  6    WEAVE  BOOM,  SECOND  STORY.    NOTE  FIRE  DOOR  WITH  BEMOVABLE 
PANELS  ABOVE  TO  ALLOW  ACCESS  TO  PULLEY  ON  LINESHAFT 


C.  H.  SMITH 


247 


FIG.  7     CARD  BOOM,  THIRD  STORY.    ENDS  SLOPED  TO  ECONOMIZE  SPACE.    NOTE 
WIRE  GLASS  WINDOW  AND  FIRE  DOOR  WITH  REMOVABLE  PANELS  ABOVE 


FIG.  8     CARD  BOOM,  THIRD  STORY.    END  VIEW  OF  BELT  ENCLOSURE. 

ALL  OUTSIDE 


BEARINGS 


248  PROTECTION  OF  MAIN  BELT  DRIVES 

creased  expense  over  ordinary  forms  of  combustible  construction  for 
the  purpose  of  separating  special  hazards  from  the  remainder  of  a 
manufacturing  room.  For  such  purposes  as  the  construction  of  bins 
to  contain  inflammable  stock,  the  segregation  of  waste  working  ma- 
chines, construction  of  lacquer  rooms,  etc.,  uses  are  constantly  being 
found  for  this  material  in  manufacturing  works. 


No.  1393  e 

THE  LIFE  HAZARD  IN  CROWDED  BUILD- 
INGS DUE  TO  INADEQUATE  EXITS 

BY  H.  F.  J.  PORTER,  NEW  YORK 
Member  of  the  Society 

Buildings  in  general  are  either  non-fireproof  or  fireproof.  The 
former  can  be  compared  to  a  pile  of  kindling  wood  out  in  the  open, 
sometimes  oil  soaked  and  always  ready  to  be  set  on  fire;  the  latter  to 
a  stove  full  of  fuel  ready  to  be  set  on  fire.  In  both  cases  the  human 
occupants  swarm  around  in  the  interstices  in  the  pile  of  fuel,  and  as 
soon  as  the  fire  starts  those  caught  in  the  fagots  have  to  work  their 
way  down  through  the  smoke  and  flames  to  the  ground  to  safety. 

2  Factory  buildings  in  particular  are  sources  of  great  danger  to 
their  large  number  of  occupants,  both  on  account  of  their  non-fireproof 
construction  and  because  of  the  obstructions  to  rapid  egress,   due 
to  haphazard  placing  of  machinery,  furniture  and  partitions  and  the 
small  number,  size  and  character  of  the  exit  facilities. 

3  Of   late,    the    unrestricted   use   of   fireproof    construction    in 
the    buildings    themselves    has    been    advocated    and    the    author 
has  recommended  the  development  of  a  form  of  exit  drill  of  the 
occupants  of  each  building  to  determine  if,  in  the  case  of  danger, 
they   could   escape   readily   from   the   building   and   if   they   could 
not,  the  alteration  of  the  exits  until  they  could.     By  "readily"  is 
meant  within  three  minutes,  for  from  many  conferences  it  was  found 
that  people  do  not  want,  nor  would  it  be  safe,  to  remain  in  a  burning 
building  longer  than  that  time. 

4  The  capacity  of  a  stairway,  if  time  is  not  a  factor  and  a 
stream  of  people  pours  into  it  only  at  the  top  and  out  of  it  from 
the  bottom,  is  unlimited;  but  if  time  is  to  be  considered  the  capacity 
is  limited  by  its  cross-sectional  area.     In  a  multi-storied  building 
with  crowds  of  people  on  each  floor  trying  at  different  points  in  its 
length  to  get  on  to  one  stairway  in  a  limited  time,  the  conditions  are 
very  different.     If  more  people  try  to  get  on  to  the  stairs  from  each 
floor  than  the  section  between  that  floor  and  the  floor  below  will 

Presented  at  the  Spring  Meeting,  Baltimore  1913,  of  THE  AMERICAN  SO- 
CIETY OF  MECHANICAL  ENGINEERS. 

249 


250  PROTECTION  OF  MAIN  BELT  DRIVES 

hold,  a  jam  will  occur  so  that  the  flow  downward  will  cease.     The 
capacity  of  this  section  is  very  limited. 

5  A  crowd  of  people  does  not  flow  like  a  liquid  composed  of 
round  smooth  molecules.     Their  soft  bodies  are  angular  in  shape 
more  like  pieces  of  rubber  with  wires  in  them  and  they  therefore 
interlock.     Clothes  present  rough  surfaces  causing  friction  and  if  the 
stairway  is  narrow  an  arch  is  apt  to  form  across  it  which  can  become 
an  obstruction  in  case  of  pressure  from  above  such  as  actually  to 
burst  the  stair  rail  or  enclosing  partition. 

6  The  capacity  of  a  stairway  of  the  average  height  of  from  10 
to  12  ft.  between  floors  and  not  less  than  22  in.  wide  would  be  one 
person  to  every  other  step  or  10  and  12  per  floor  respectively,  and  if 
the  width  is  doubled  (not  less  than  44  in.)  so  that  two  people  can  come 
down  abreast,  twice  those  numbers  or  20  and  24.     If  a  stairway  has 
winders  in  it,  its  capacity  is  reduced  50  per  cent.     One  person  can 
descend  a  single  flight  of  such  steps  10  to  12  ft.  high  in  10  seconds, 
striking  a  gait  which  he  can  maintain  for  seven  or  eight  flights  of 
steps.     After  that  he  goes  slower,  making  the  tenth  flight  in  about 
11  or  12  seconds.    Every  person  added  in  single  file  adds  1  second  to 
this  time.    A  double  file  takes  no  longer  if  the  stairs  are  double  width. 
Thus  it  will  take  10  seconds  for  10  or  20  people,  that  is,  the  full 
capacity  of  a  flight  of  steps,  to  come  down  one  story.     The  capacity 
of  a  stairway  may  be  thus  increased  by  widening  it  in  multiples  of 
22  in.     A  crowd  of  people  cannot  be  depended  upon  to  come  down 
more  than  ten  stories.    One  or  more  of  them  will  give  out,  and  demand 
the  attention  of  others.  Those  who  do  get  down  will  be  severely  taxed. 
The  total  time  required  to  empty  a  building  is  determined  by  the 
time  required  to  empty  either  the  floor  farthest  from  the  ground  or 
the  floor  occupied  by  the  greatest  number  of  people. 

FORMULA  FOR  EMPTYING  A  FLOOR  BY  ONE  STAIRWAY 

Number  of  couples  (number  of  people  divided  by  2) c 

Time  of  formation  in  line  after  signal,  seconds 10 

Time  one  couple  takes  to  march  to  top  of  stairs,  seconds 10 

Time  each  couple  takes  to  pass  through  door  at  top  of  stairs,  seconds 1 

Number  of  stair  flights  (one  less  than  number  of  floors) / 

Time  of  one  couple  to  descend  one  flight  of  stairs,  seconds 10 

Time  of  one  couple  to  go  from  foot  of  stairs  to  street,  seconds 10 

Total  time  =  T  =  30  +  cl  +  /10 

Example     Time  of  emptying  100  people  from  tenth  floor 
T  =  30  +  50  +  90  ==  170  seconds  =  2  minutes,  50  seconds 


H.  F.  J.  PORTER  251 

Example     Time  of  emptying  a  ten-story  building  with  20  people 
on  each  floor  is  the  same  as  emptying  20  people  from  tenth  floor. 
T  —  30  -f  10  +  90  =  130  =  2  minutes,  10  seconds 

7  Tests  of  the  capacity  of  fire  escapes  in  a  limited  time  gave 
the  following  results:     A  straight  ladder,   2  per  floor;  ladder  set 
at  50  to  60  deg.  with  the  horizontal  requiring  people  to  go  down 
backwards  3  to  4  per  floor;  stairs  30  in.  wide,  10  to  12  per  floor; 
and  the  modern  outside  stairway  with  a  mezzanine  platform  40  in. 
wide,  20  to  24  per  floor,  the  same  as  an  inside  stairway.    Fire  escapes 
are  usually  so  exposed  to  flames  from  windows  opening  upon  them 
that  they  are  more  often  fire  traps  than  fire  escapes.     They  should 
be  prohibited  by  law  and  safer  methods  of  escape  provided. 

8  In  order  to  insure  the  safety  of  the  occupants  of  a  building  in 
case  of  emergency  one  of  two  things  has  to  be  done :    (a)  there  should 
be  two  stairways  so  that  if  one  is  cut  off  by  flames  or  smoke  the  other 
can  be  used  and  the  number  of  occupants  reduced  on  each  floor  to 
meet  the  limited  capacity  of  the  part  of  the  stairway  between  floors, 
or  (&)  the  number  of  stairways  increased  so  as  to  have  two  separate 
and  independent  stairways  from  each  floor  to  the  ground  with  its 
own  exit  from  the  building.     People  can  then  pour  into  the  top  of 
whichever  one  is  not  cut  off  by  the  fire  and  continue  down  and  out 
at  the  bottom  without  colliding  with  those  from  any  other  floor. 
Fire  drills  installed  under  either  of  these  conditions  worked  more 
or  less  satisfactorily,  and  the  author  tried  unsuccessfully  for  years  to 
have  ordinances  passed  in  New  York  City  and  legislation  enacted  at 
Albany,  making  them  mandatory,  but  the  expense  of  changes  in  the 
buildings  and  the  idea  of  having  employees  walk  out  of  a  factory  while 
manufacturing  operations  were  under  way,  upon  the  sounding  of  an 
unexpected  signal,  did  not  appeal  to  factory  proprietors  as  practical. 
It  required  holocausts  in  New  Jersey,  Pennsylvania  and  New  York 
finally  to  bring  about  the  legislation  in  those  states. 

9  As  time  passed,  however,  the  author  developed  what  might  be 
termed  an  exit  test  in  factories  which  presented  the  opportunity  and 
found  to  his  astonishment  that  almost  without  exception,  exit  facilities 
adequate  for  handling  the  regular  number  of  occupants  under  emer- 
gency conditions,  were  lacking. 

10  This  situation  has  probably  developed  with  the  rapid  growth 
of  industry  where  a  factory  building  had  been  built  to  accommodate 
a  certain  number  of  people,  and  then,  as  the  business  grew,  more 
people  were  accommodated  without  realizing  that  each   additional 
person  became  an  increment  of  danger  to  all.     Or,  if  the  danger  was 


252  LIFE  HAZARD  IN  CROWDED  BUILDINGS 

at  all  appreciated,  some  means  of  escape  from  windows  was  supplied 
which  might  be  anything  from  a  rope  to  a  ladder.  After  this  condition 
had  become  general  it  crystallized  into  custom,  and  new  buildings 
with  exit  facilities  inadequate  for  their  occupancy  were  designed, 
erected  and  accepted  as  safe.  Eopes  were  followed  by  ladders,  and 
these  in  turn  by  fire  escapes  which  became  in  time  an  established 
necessity. 

11  Engineers,  when  called  upon  to  supply  a  mechanism,   are 
expected  to  have  it  subjected  to  a  working  test,  which  it  must  pass 
before  they  get  paid  for  it;  but  architects  and  builders  have  never 
been  called  upon  to  demonstrate  by  actual  test  that  the  facilities 
which   they  have   supplied   in   their   buildings   for   tne   purpose   of 
emptying  them  under  emergency  conditions  will  actually  work,  and 
this  notwithstanding  repeated  instances  of  panic  congestion  on  stairs, 
of  people  being  burned  to  death  on  fire  escapes,  of  elevators  sticking 
from  the  warping  of  their  runways  from  heat,  etc. 

12  When  subjected  to  test  these  exit  facilities  in  many  buildings 
have  been  found  to  be  entirely  wanting  in  adequacy,  and  when  this 
fact  was  brought  to  the  attention  of  those  who  were  responsible,  it  has 
been  surprising  to  find  how  readily  they  accepted  the  criticism.     On 
the  other  hand,  those  who  possess  these  unemptiable  buildings  are 
sceptical  of  such  statements  and  unwilling  to  be  persuaded  that  the 
buildings  are  not  safe.    They  point  to  all  the  other  buildings  erected  by 
reputable  architects  and  builders  and  naturally  are  incredulous. 

13  In  order  to  empty  these  buildings,  additional  stairways  had 
to  be  built  and  fire  drills  developed  to  take  the  people  out.     Such 
changes  in  the  building  are  expensive,  for  two  stairways  have  to  be 
installed  from  each  floor  to  the  ground,  so  that  if  one  is  cut  off  by  a 
fire,  the  other  can  be  used.    In  many-storied  buildings  the  number  of 
stairways  required  becomes  impractical.     In  addition  fire  drills  are 
expensive  to  operate,  for  they  involve  not  only  loss  of  time  of  operatives 
and  a  break  in  the  continuity  of  the  process  of  manufacture,  but  the 
actual  going  down  stairs  and  return  of  people,  some  of  whom  may  be 
lame,  others  affected  by  a  weak  heart  or  lungs,  others  anaemic  or 
organically  weak,  reduce  the  efficiency  of  the  working  force  for  a  very 
appreciable  time.    If  the  drill  takes  place  at  the  end  of  the  day  this 
criticism  might  be  modified  slightly. 

14  -Such  is  the  situation  in  the  usual  type  of  factory  building  to 
be  found  in  the  average  town  where  ground  is  cheap,  buildings  large 
and  stairways  broad.     Turning  now  to  the  loft  building  used  for 


H.  F.  J.  PORTER 


253 


factory  purposes,  the  conditions  as  regards  emptiability  are  found  to 
be  very  much  worse  and  have  to  be  corrected  in  a  different  manner. 

15  Let  us  consider  for  the  moment  a  one-story  or  ground-floor 
factory  building  with  a  doorway  at  each  side,  one  of  which  is  cut  off 
by  a  fire.  The  people  can  march  out  horizontally  through  the  other 
doorway  and  nothing  will  inpede  this  horizontal  exit  except  the  size 
of  the  doorway.  If  this  is  2*2  in.  wide,  a  single  file  of  people  can  pass 
out  in  an  orderly  manner  at  the  rate  of  one  person  every  second.  If 


FIG.  1     FLOOR  PLAN  OF  TYPICAL  LOFT  BUILDING  SHOWING  FIRE  WALL  WITH 

DOORWAYS 

it  is  44  in.  wide,  a  line  of  people  two  abreast  can  pass  out  in  the  same 
time.  One  hundred  people  can  make  their  exit  through  one  44-in. 
door,  therefore,  in  50  seconds,  or  say  one  minute. 

16  Now  put  another  factory  on  top  of  this  one  with  one  hundred 
people  in  it.  The  doorway  at  each  side  will  have  to  open  on  stairways 
which  lead  down  to  the  doorways  constituting  the  exits  from  the 
factory  below.  Suppose  a  fire  occurs  on  the  floor  below,  cutting  oft* 
one  of  these  exits,  the  100  people  on  the  lower  floor  immediately 


254  LIFE  HAZARD  IN  CROWDED  BUILDINGS 

proceed  to  make  their  horizontal  exit,  while  those  on  the  upper  floor 
proceed  to  make  a  vertical  downward  exit  to  reach  the  doorway  out 
of  which  those  below  are  moving.  The  result  is  of  course  a  collision, 
the  stream  of  people  from  upstairs  coming  down  upon  the  stream  of 
people  on  the  ground  floor  on  their  way  out.  This  collision  prevents 
both  the  upstairs  stream  from  coming  down  and  the  down-stairs 
stream  from  going  out.  There  is  a  complete  lock,  and  the  building 
does  not  empty. 

17  Not  only  have  we  put  one  factory  on  another  in  the  case  of 
our  loft  building,  but  we  have  piled  factory  on  factory  until  we  have 
from  10  to  30  and  more,  one  on  top  of  the  other;  and  each  employing 
from  100  to  300  or  more  people.     In  cases  of  emergency  as  in  the 
Asch  Building  fire,  there  are  only  two  courses  for  the  occupants: 
one  is  to  burn  to  death,  and  the  other  to  jump  to  death — "to  burn  up 
or  jump  down." 

18  It  is  impossible  to  reduce  the  number  of  people  per  floor 
to  the  capacity  of  the  stairs,  say  24  per  floor.     Even  if  that  number 
would  be  all  that  a  business  required,  in  case  of  emergency  they  would 
have  to  go  downstairs,  and  it  is  a  physical  impossibility  for  people 
to  stand  the  exertion  of  a  trip  down  more  than  ten  stories  without 
resting ;  and  when  they  stop  to  rest  they  block  the  stream  and  obstruct 
its  exit.     Under  these  circumstances  it  is  necessary  to  develop  some 
other  method  for  people  in  high  buildings  to  secure  safety.     The 
following  suggestion  is  offered  to  meet  the  situation : 

19  It  has  been  seen  that  a  horizontal  escape  by  people  on  the 
ground  floor  is  readily  secured.    Let  us  see  if  a  horizontal  escape  to 
safety  for  people  at  any  height  from  the  ground  can  be  developed. 
Suppose  a  wall  is  built  across  the  building  from  cellar  to  roof  prac- 
tically bisecting  it  in  a  way  so  as  to  have  a  stairway  and  elevator 
on  each  side.    This  wall  should  have  at  least  two  doorways  in  it  at  a 
considerable   distance   from   each   other   and   closed    by    self-closing 
fireproof  doors  (Fig.  1). 

20  It  is  improbable  that  a  fire  will  occur  on  both  sides  of  this 
wall  simultaneously.     It  could  occur  only  by  incendiary  origin,  and 
that    would    hardly    be    possible    in    working    hours.      Should    one 
occur  on  either  side,  the  people  on  that  side  would  go  through  the 
doorways  in  the  fire  wall,  close  the  doors  after  them  and  be  perfectly 
safe.     That  half  of  the  building  in  which  the  fire  might  be  should 
be  emptied  in  less  than  a  minute  if  there  were  no  more  than  100 
people  on  each  floor  to  pass  through  one  doorway  44  in.  wide.    If  the 
principle  of  the  horizontal  escape  presented  by  the  fire  wall  is  included 


H.  F.  J.  PORTER 


255 


in  the  design  of  new  buildings  a  most  satisfactory  method  of  securing 
safety  at  comparatively  small  expense  will  be  offered. 

21  In  every  way  possible  the  horizontal  escape  should  be  developed 
in  old  buildings  and  the  vertical  escape  subordinated.  Factory  build- 
ings adjoining  one  another  may  have  doorways  through  their  sides 
connecting  them  on  various  floors  closed  by  fireproof  self-closing  doors, 
or  may  be  connected  by  outside  balconies  built  around  the  party  walls ; 
or,  if  of  different  heights,  doors  in  the  sides  of  one  may  lead  out  on  the 
roofs  of  the  others. 

2»2  The  fire  wall  bisecting  the  building  as  described  makes 
practically  two  buildings,  each  provided  with  elevators  and  stairways. 


E le  vators <--'' 

•it 


FIG.  2     DEPARTMENT  STORE  FLOOR  PLAN  SHOWING  PRESENT  ARRANGEMENT 
OF  FIRE  WALLS,  ELEVATORS  AND  STAIRS 

A  fire  on  one  side  of  the  wall  would  be  confined  to  half  the  building, 
and  therefore  the  property  loss  would  be  reduced  one-half.  Only 
one-half  the  people  would  be  endangered  and  have  to  move,  and  the 
distance  they  would  have  to  go  would  be  only  one-half  what  it  would 
be  if  they  were  on  the  ground  floor  of  a  building  without  a  fire  wall. 
They  could  remain  on  the  same  floor  till  the  fire  was  extinguished, 
or  could  go  down  to  the  ground  by  the  elevators  operating  under 
normal  conditions. 

23  The  fire  wall  eliminates  the  necessity  for  a  fire  drill  with  its 
accompanying  objections.  Of  course  all  buildings  occupied  by  many 
people  should  have  a  fire  alarm  signal  system  in  them  to  advise  the 
people  promptly  of  their  danger.  In  buildings  where  there  is  a  fire 


256 


LIFE  HAZARD  IN  CROWDED  BUILDINGS 


wall  the  signals  should  be  arranged  so  that  in  case  a  fire  should 
occur  on  one  side  of  the  fire  wall  on  any  floor,  a  bell  on  each  floor 
on  the  same  side  of  the  fire  wall  would  ring,  indicating  on  which  floor 
the  fire  is.  Then  all  the  people  on  that  floor  and  above  it  should  pass 
through  the  fire  wall  and  close  the  doors.  Those  below  need  not 
disturb  themselves  until  the  fire  threatens  them,  and  then  they  too 
can  pass  through  the  fire  wall. 

24:     There    are    certain    other    safety    devices    which    should    be 
supplied  in  factories  to  protect  the  lives  of  the  operatives  from  fire. 


FIG.  3     SUGGESTED  ARRANGEMENT  OF  FIRE  WALLS,  ELEVATORS  AND  STAIRS 
FOR  DEPARTMENT  STORE 

One  of  these  is  metal-framed  windows  with  wire  glass.  These  are 
made  so  as  to  close  automatically  in  case  of  fire,  thus  preventing  the 
latter  from  spreading  upwards  from  floor  to  floor  outside  of  the 
building. 

25  Another  safety   device  is   automatic  sprinklers  which  serve 
to  extinguish  fires  in  their  incipiency.     All  doors  should  be  made  to 
swing  outward,  and  where  they  open  on  a  hall  or  stair  landing  they 
should  be  vestibuled,  so  as  not  to  obstruct  the  passage  way.     Sliding 
doors  should  be  avoided  if  possible,  as  they  are  apt  to  stick  or  jam  by 
pressure  of  people  upon  them. 

26  Each  floor  of  our  typical  loft  buildings  is  say  100  ft.  by 
100  ft.  by  10  ft.  and  therefore  contains  100,000  cu.  ft.  of  air.     The 
laws  of  New  York  and  many  other  states  require  250  cu.  ft.  of  air  per 
person  as  a  limitation  of  occupancy.     This  limits  the  number  of 


H.  F.  J.  PORTER  257 

people  per  floor  in  a  building  of  this  size  to  400  and  if  the  stairways 
were  44  in.  wide  (and  there  are  none  now  over  36  in.)  at  most  only 
40  per  floor  could  possibly  go  down  them  even  if  the  other  360  would 
let  them. 

27  With  the  fire  wall  only  200  of  the  400  people  on  each  floor 
would  have  to  move,  and  if  there  were  two  doorways  in  the  fire  wall 
at  some  distance  from  each  other,  they  could  reach  safety  through 
them  in  one  minute,  or  if  one  were  cut  off  by  the  fire,  all  could  pass 
through  the  other  easily  in  two  minutes.     More  doorways  can  be 
introduced,  and  thus  the  time  of  exit  could  be  lowered  still  further. 

28  .  An  effort  is  being  made  to  increase  the  amount  of  air  space 
required  per  person  from  250  to  500  cu.  ft.,  which  would  reduce  the 
number  of  people  per  floor  to  200,  of  whom  only  100  would  have  to 
move,  and  they  could  easily  reach  safety  in  one  minute. 

29  The  stairways  and  elevators  should  be  enclosed  in  fireproof 
walls  to  prevent  a  fire  on  one  floor  continuing  upward  and  setting 
the  other  floors  on  fire.  The  ceiling  of  the  basement  where  the 
machinery  is  located  should  be  fireproof,  and  should  not  be  pierced 
inside  of  the  building,  so  that  a  fire  there  would  not  reach  the  elevator 
shafts. 

30  Fire  escapes  which  are  simply  stairs  and  possess  dangerous 
features  not  only  of  limitations  as  to  size,  but  of  accessibility  for 
flames  and  smoke,  should  be  looked  upon  as  evidence  of  the  incom- 
petence or  ignorance,  or  worse,  of  the  architect,  builder,  or  owner, 
and  prohibited  by  law  under  a  heavy  fine.    They  are  not  only  danger- 
ous to  life  by  giving  a  false  confidence  in  their  adequacy  for  escape,  but 
they  destroy  the  appearance  of  the  building.     Our  cities  should  be 
built  without  such  architectural  blemishes. 

31  Fire  escapes  of  the  chute  type  are  tubes  with  a  smooth  helix 
instead   of   steps.*    If   the   only   opening  is   at   the   top   they   have 
considerable  capacity.     They  soon  rust,  however,  and  at  best  are  not 
to  be  considered  seriously  in  comparison  with  other  means  of  safe 
exit.    People  cannot  enter  them  at  different  floors  while  a  stream  of 
people  is  passing  down  from  above. 

32  The  smoke-proof    tower,    claimed    to    have    originated    in 
Philadelphia,  is  the  latest  improvement  in  the  line  of  fire  escapes. 
It  is   simply   an   enclosed   stairway  on  the  outside   of   a  building, 
but  cannot,  be  reached  except  by  going  out  of  doors.     Its  special 
claim  is  that  smoke  and  flames  cannot  get  into  it.     It  has,  however, 
no  more  capacity  than  any  other  stairway,  and  as  its  approach  is 
always  open  to  the  weather  and  its  interior  is  always  more  or  less 


258  LIFE  HAZARD  IN  CROWDED  BUILDINGS 

dark,  it  is  never  used  in  ordinary  service  and  becomes  neglected. 
These  monuments  to  architectural  incompetency  can  be  seen  here  and 
there  filled  with  the  dust  and  accumulated  rubbish  of  every  unused 
open  space.  When  a  time  arrives  for  using  them  everybody  has  for- 
gotten their  existence.  During  the  last  year  or  two,  notwithstanding 
the  protests  of  many,  a  great  many  new  buildings  have  been  con- 
structed, especially  in  New  York  City,  with  these  monstrosities  on 
them,  and  have  been  accepted  by  the  building  department  in  all 
seriousness. 

33  The  fire  wall  should  be  introduced  into  all  buildings  where 
the  public  congregates  in  large  numbers.     Large  department  stores, 
which  on  certain  days  are  said  to  accommodate  several  thousand 
people  per  floor,  are  very  dangerous  places  at  present.     A  fire,  or  a 
panic  without  a  fire,  might  cause  a  fearful  tragedy.     It  is  criminal 
for  their  owners  to  object  to  fire  walls  and  offer  as  an  excuse  that  they 
would  obstruct  the  vista.     Certain  cities  require  fire  walls  in  such 
buildings  now  as  a  property  protection,  and  the  vista  is  dispensed 
with   without   comment.      The   department   stores   of    Philadelphia 
are  so  divided;  John  Wanamaker's  new  store  there  is  divided  by  two 
such  walls  as  shown  in  Fig.  2.    The  exit  facilities  in  it,  however,  are 
badly  arranged,  for  the  architect  apparently  did  not  think  of  the  life 
hazard  of  its  occupants,  and  designed  the  fire  walls  to  protect  property 
only.  Fig.  3  shows  how  the  building  might  be  redesigned  so  as  to  be 
safer.     It  should  be  noted  that  the  elevators  are  removed  from  the 
fire  wall  so  that  people  trying  to  go  down  in  them  would  not  block 
the  doorways  of  the  fire  wall  and  prevent  others  coming  through 
them.    The  stairways  are  situated  as  far  from  the  fire  wall  as  possible 
and  should  be  enclosed  by  fireproof  partitions. 

34  Churches,  assembly  halls  and  similar  ground-floor  buildings 
should  have  their  floor  fireproof   and  unpierced  so   that  any   fire 
occurring  in  the  basement  would  not  endanger  the  occupants  of  the 
main  building. 

35  Moving  picture  buildings,  theaters,  etc.,  should  be  redesigned 
(Fig.  4).  People  come  out  of  them  by  the  way  they  go  in,  and  in 
case  of  emergency  all  crowd  into  the  narrow  aisles.  These  aisles 
should  be  turned  across  the  room  and  lead  directly  to  courts  opening 
on  the  street  in  a  way  such  that  streams  of  people  will  not  collide. 
The  various  balconies  and  galleries  should  have  foyers  behind  fire 
walls  with  separate  stairs  and  street  exits  so  that  patrons'  will  not 
have  to  mingle  with  those  making  their  exit  from  the  lower  floors. 


H.  F.  J.  PORTER 


259 


260  LIFE  HAZARD  IN  CROWDED  BUILDINGS 

36  Every  school  building  should  be  divided  by  a  fire  wall 
providing  a  horizontal  exit  on  each  floor,  so  that  the  children  will  not 
have  to  be  drilled  to  go  downstairs  in  case  of  fire. 

3-7  Hospitals  where  the  inmates  are  bedridden,  blind,  lame, 
invalid,  imbecile,  or  otherwise  helpless,  can  be  made  safe  by  the 
introduction  of  the  fire  wall  between  wards,  and  in  case  of  fire  those 
who  are  bedridden  can  be  wheeled  on  their  beds  through  the  doorways, 
and  those  who  are  up  and  about  can  walk  through  them. 

38.  Hotels  and  apartment  buildings  can  so  easily  have  a  fire 
wall  developed  in  them  that  it  need  only  be  referred  to  here  in 
passing.  Even  the  private  residence  where  only  a  few  pople  occupy 
a  floor  can  be  made  safe  in  this  way.  The  back  stairway  should  be 
enclosed  in  a  fireproof  partition,  and  in  case  of  a  fire  instead  of 
everybody  having  to  go  downstairs  through  the  smoke  and  flames, 
or  having  to  jump  from  windows,  the  people  on  each  floor  have 
simply  to  pass  through  the  fireproof  door  and  go  down  stairs  in 
safety.  In  large  residences  where  there  is  a  servants'  quarters  in 
connection  with  the  back  stairs,  the  building  would  be  bisected  and- 
the  people  on  either  side  of  the  wall  would  be  able  to  carry  their 
clothing  and  perhaps  much  household  and  personal  property  to 
safety. 

39  Two   years   ago   the   National   Fire   Protection   Association 
appointed  a  committee  of  which  the  author  was  a  member  to  draft 
suggestions  for  the  organization  and  execution  of  fire  drills.    This  com- 
mittee made  its  report  to  the  annual  meeting  of  the  association  held 
in  Chicago  last  May,  and  it  was  adopted  with  slight  modifications. 
A  prefatory  note  to  this  report  is  as  follows: 

Many  so-ealled  fire  drills,  outside  fire  escapes,  and  similar  practices  and  de- 
vices are  generally  insufficient,  often  dangerous,  and  therefore  misleading  sub- 
stitutes for  rational  exit  facilities,  and  are  a  manifestation  of  improper  design 
and  construction  of  our  buildings.  A  stairway  connecting  many  stories  will 
accommodate  only  a  limited  number  of  people.  Stairways  are,  therefore,  dan- 
gerous means  of  exit  for  crowds.  Congestion  is  bound  to  occur  in  them  when 
used  under  stress  of  excitement  owing  to  their  limitations. 

The  primary  object  of  the  exit  drill  is  to  determine  if  the  building  is 
properly  designed  so  that  in  the  emergency  of  a  fire  its  occupants  would  be  able 
to  effect  their  escape  readily  without  the  probability  of  injury  from  stairway 
or  other  congestion  which  inevitably  causes  panic.  This  test  should  be  occa- 
sionally repeated  to  insure  the  continuous  maintenance  of  safe  conditions. 

40  The   author   advocates   legislation,    requiring   three   things: 
(a)  Architects   and  builders  should   be   prohibited   from   designing 
buildings  which  cannot  be  emptied  within  3  minutes  after  a  given 


H.  F.  J.  PORTER  261 

signal,  (b)  The  municipal  authorities  should  be  required  to  institute 
an  exit  test  in  each  building  to  determine,  before  it  is  accepted,  if  it 
can  be  emptied  of  its  occupants  in  3  minutes.  If  it  cannot  pass  this 
test  it  will  not  be  accepted  and  must  be  altered  until  it  can  pass  the 
test,  (c)  Afterwards  the  proper  authorities  will  be  required  to  repeat 
the  exit  test  from  time  to  time,  to  see  that  the  safe  conditions 
originally  established  are  maintained. 


1393/ 

DISCUSSION  ON  FIRE  PROTECTION 

W.  H.  KEKERSON  referred  to  the  statement  of  Mr.  Porter  that 
people  do  not  want,  nor  is  it  safe  for  them  to  remain  in  a  burning 
building  more  than  three  minutes.  He  said  that  he  was  present  at 
the  start  of  a  very  quick  fire  where  the  people  in  the  building  were 
reluctant  to  stay  at  all.  They  got  out  of  the  building  by  jumping 
almost  as  quickly  as  they  could  run  to  the  side  walls.  Even  with  ade- 
quate exits  it  was  plainly  evident  that  danger  could  not  be  eliminated. 
In  buildings  where  operatives  were  working  under  crowded  condi- 
tions some  people  would  be  burned  or  crushed  before  they  could  get 
out  in  case  of  a  severe  fire,  even  if  the  walls  were  open  all  the  way 
around,  owing  to  the  furniture,  machines,  etc.,  being  closely  grouped. 
The  panic  following  an  incipient  fire  was  often  worse  than  the  fire 
itself  and  did  more  damage.  In  some  of  our  large  cities,  the  streets 
in  the  neighborhood  of  office  buildings  and  factories  are  so  narrow 
and  so  hemmed  in  by  the  crowds  rushing  toward  the  building  in  case 
of  a  fire  that  there  would  not  be  room  enough  in  the  street  to  accom- 
modate the  operatives  who  were  leaving.  This  was  certainly  true  of 
some  loft  buildings  in  New  York  City. 

Eegarding  the  use  of  the  fire  wall,  while  it  is  of  great  value 
in  certain  cases  and  places,  it  is  not  altogether  dependable.  Was 
it  not  conceivable  that  fires  could  not  start  on  both  sides  of  a  par- 
tition at  once  ?  There  were  many  conditions  under  which  a  fire  would 
rapidly  spread  to  both  sides  of  a  partition  even  if  it  did  not  start  on 
both  sides,  as  for  example  in  a  flash  fire. 

The  author  very  properly  said  that  sliding  doors  inside  of  par- 
titions were  dangerous;  but  what  of  swing  doors?  These  should 
always  open  outward,  but  what  was  "outward"  in  a  partition  that 
must  be  used  in  both  directions?  "Where  communication  was  estab- 
lished between  adjacent  buildings  even,  it  was  inevitable  that  one  of 
the  doors  would  open  the  wrong  way. 

There  was  only  one  paragraph  in  the  paper  about  preventive 
methods  through  the  use  of  automatic  apparatus  in  conjunction  with 
other  things  for  preventing  fire  at  the  start.  It  was  unfortunate 
that  this  was  not  included  in  a  paper  of  the  general  scope  of  the  one 
under  discussion. 


Presented   at   the   Spring   Meeting,    Baltimore    1913,    of    THE   AMERICAN 
SOCIETY  OF  MECHANICAL  ENGINEERS. 

263 


264  DISCUSSION  ON  FIRE  PROTECTION 

He  believed  that  it  would  be  impossible  to  enforce  the  legislation 
recommended  in  the  last  paragraph  of  the  paper  to  prevent  archi- 
tects from  designing  buildings  which  could  be  emptied  in  3  min- 
utes. Before  construction  such  a  matter  was  a  question  of  opinion 
rather  than  fact.  Moreover,  operatives  could  not  be  prevented  from 
crowding  or  becoming  panic  stricken  in  the  event  of  a  fire  and  it  was 
doubtful  under  such  circumstances  whether  many  a  properly  designed 
building  could  be  emptied  in  3  minutes  even  if  it  were  possible  to 
enforce  the  first  recommendation. 

HENRY  HESS.  I  am  neither  an  insurance  nor  a  sprinkler  man.  I 
have  had  some  experience  putting  up  factory  buildings  and  running 
the  establishment  afterwards.  One  of  my  most  interesting  experi- 
ences of  that  character  was  in  building  a  large  tool  works  in  Germany. 
The  first  thing  I  ran  afoul  of  was  the  law.  I  bring  this  up  particu- 
larly because  Professor  Kenerson  has  indicated  his  belief  that  ade- 
quate legislation  was  absolutely  impossible,  if  not  as  to  securing  it  in 
the  first  place,  then  ae  to  its  later  enforcement.  Now  that  is  a  ques- 
tion of  the  will  of  the  community.  If  the  community  really  desires 
enforcement  of  law  it  will  see  to  such  enforcement.  Fire  wall  parti- 
tions such  as  Mr.  Porter  advocates  are  very  useful.  In  the  case  of  the 
German  factory  partitions  were  installed  in  certain  cases  and  were 
not  insisted  upon  in  others ;  but  there  was  an  insistence  upon  one  other 
thing  of  possibly  far  greater  importance.  The  authorities  determined 
a  central  point  for  each  floor  area,  considered  the  number  of  people 
at  work  in  that  area,  and  then  insisted  that  there  must  be  an  ade- 
quate fireproof  staircase  within  a  certain  distance  of  that  central 
point.  The  size  of  the  stairway  was  made  to  increase  with  the  in- 
crease of  that  distance,  which  latter  was  not  permitted  to  exceed  a 
certain  limit.  Moreover,  a  stairway  had  to  be  provided  not  merely  at 
one  end,  but  at  two  ends  at  diagonal  corners  so  that  there  was  a  possi- 
bility of  reaching  a  stairway  in  two  directions  from  a  central  point. 
The  law  does  not  permit  overcrowding.  Such  conditions  as  obtain 
in  New  York  City  loft  buildings  would  not  be  tolerated  in  the  coun- 
tries from  which  the  people  who  run  the  industries  in  these  lofts  have 
come  to  us.  Why  should  our  communities  grant  them  such  permis- 
sion here?  Panic  cannot  be  altogether  guarded  against  in  the  con- 
struction of  a  building.  (Sprinklers  do  not  constitute  a  full  safeguard. 
In  fact  if  you  were  to  send  down  a  douche  of  water  upon  an  excitable 
woman  when  she  smells  smoke  or  sees  fire  you  would  most  certainly 
not  cool  her  down.  Provide  what  safeguards  you  will,  always  keep 


DISCUSSION  265 

the  crowds  down  to  a  point  where  even  panic  stricken  people  cannot 
seriously  jam. 

GEO.  I.  ROCKWOOD.  As  one  interested  in  the  general  subject  of 
fire  protection,  I  have  followed  closely  the  fire  statistics  of  the  last 
seven  or  eight  years  as  given  out  by  the  National  Fire  Protection 
Association  and  the  Factory  Mutual  Fire  Insurance  Companies.  I 
have  also  had  experience  with  the  manner  in  which  automatic  sprink- 
lers operate  to  save  human  life,  having  been  responsible  for  the  in- 
stallation of  many  hundreds  of  thousands  of  sprinkler  heads;  so  that 
with  that  experience  back  of  me  I  want  to  say  that  no  one  so  far  as  I 
know  has  really  done  more  than  has  Mr.  Porter  to  convert  the  rather 
obstinate  architectural  profession,  as  well  as  the  equally  obstinate 
members  of  the  profession  of  fire  protection  engineering,  to  the  use 
of  this  very  obvious  device  for  getting  operatives  and  others  out  of  a 
burning  room  and  into  a  place  of  safety. 

The  way  of  the  reformer  is  proverbially  difficult,  but  it  seems  to 
me  that  those  responsible  for  the  design  of  loft  buildings  have  been 
particularly  slow  in  appreciating  Mr.  Porter's  work.  Very  likely  the 
reason  for  this  will  be  found  in  Mr.  Porter's  scarcely  concealed  con- 
tempt for  the  automatic  sprinkler  as  a  life-saving  device,  but  neither 
Mr.  Porter  nor  anyone  else  has  yet  made  any  proper  inquiry  into  the 
history  of  automatic  sprinklers,  considered  solely  from  the  point  of 
view  of  their  use  as  life  savers.  They  have  been  regarded  altogether 
as  property  savers,  and  are  installed  in  buildings  for  that  purpose. 
It  is  perfectly  clear  that  every  time  a  sprinkler  operates  successfully 
in  a  building  containing  human  beings  it  is  potentially  a  life  saver. 
The  question  narrows  down,  therefore,  to  the  effect  of  sprinklers  in 
preventing  panic  conditions  in  buildings.  Do  they  prevent  panics  or 
can  they  be  made  to  prevent  them  ?  We  need  a  little  further  light  on 
this  subject  before  we  can  dogmatize  to  advantage  either  way,  but 
I  feel  confident  that  the  solution  of  the  problem  of  saving  human  life 
is  a  function  equally  of  the  use  of  Mr.  Porter's  centrally  located  in- 
combustible partitions  and  the  proper  use  of  automatic  sprinklers. 

In  the  average  case  of  a  fire  extinguished  by  automatic  sprink- 
lers three  or  four  heads  are  all  that  open  to  effect  the  result.  In 
the  case  of  quick  flash  fires  an  entire  roomful  of  sprinklers  may 
open,  seemingly  at  once,  without  any  appreciable  interval  of  time 
between  the  setting  of  the  fire  and  the  operation  of  the  sprinklers. 
The  question  naturally  arises,  would  such  instant  out-pouring  of 
water  be  an  advantage  or  a  disadvantage  to  a  room  more  or  less 


266  DISCUSSION  ON  FIEE  PROTECTION 

crowded  with  operatives  No  sane  man  would  take  the  ground  that 
he  would  rather  be  in  such  a  room,  under  those  conditions,  without 
sprinklers.  In  a  recent  case  where  a  flash  fire  occurred  in  the  first 
floor  of  a  three-story  factory  filled  with  people  on  every  floor,  a  can 
of  material  in  which  gasolene  was  an  ingredient  took  fire,  with 
the  curious  result  that,  although  the  room  was  not  a  particularly 
large  one,  and  there  were  many  men  at  work  in  it,  not  a  man  got 
out  of  the  room  without  getting  wet.  They  said  afterwards  that  there 
seemed  to  be  no  interval  of  time  between  the  instant  when  the  can 
flashed  up  and  the  subsequent  out-pouring  of  water  from  all  of  the 
sprinkler  heads  in  the  room. 

It  might  be  thought  that  where  a  factory  has  a  good  deal  of 
material  out  of  which,  say,  straw  hats,  or  lingerie,  are  made,  the 
rapidity  with  which  the  fire,  once  started,  would  propagate  would 
insure  the  injury  of  everybody  in  the  room.  Such  a  view  would 
fail  entirely  to  take  into  account  the  fact  that  when  the  fire  starts 
the  heated  gases  almost  instantly  rise  to  the  ceiling  where  they  pro- 
ceed to  mushroom  out  and  open  the  sprinkler  heads  one  after  another 
much  faster  than  the  fire  can  propagate  itself  in  the  material  on  the 
floor.  This  is  not  a  matter  of  speculation ;  it  is  an  observed  fact. 

There  are  classes  of  buildings  in  which  there  are  so  many  con- 
cealed spaces  in  the  wooden  walls,  wooden  partitions  and  wooden 
floors,  that  a  heavy  fire  may  conceivably  get  strong  headway  in  some 
concealed  space  before  it  shows  itself.  Under  such  circumstances,  the 
sprinklers  operate  at  a  disadvantage  and  merely  act  as  a  check  to 
the  spread  of  the  flames  until  the  arrival  of  the  fire  department.  But 
even  then  they  often  make  it  possible  for  the  firemen  to  carry  their 
hose  to  the  very  center  of  the  fire,  and  thus  are  the  primary  cause  of 
its  final  extinguishment. 

Mr.  Porter  would  do  well  to  add  to  his  crusade  in  favor  of  a 
central  figure  resistant  partition,  with  separate  means  of  egress  on 
opposite  sides  of  it,  a  further  demand  for  the  installation  of  auto- 
matic sprinklers,  and  he  will  be  surprised  to  see  how  much  more 
quickly  his  original  effort  at  reform  will  succeed; 

HARRINGTON  EMERSON.  In  making  comparative  investigations  of 
American  and  foreign  cities  what  strikes  one  most  is  the  much  lower 
fire  loss  in  German  cities  than  in  American  cities.  The  reason  is  that 
different  ideals  have  been  pursued.  Our  ideal  is  to  get  there  imme- 
diately. In  an  international  test  of  different  fire  companies  at  Ber- 
lin about  20  years  ago  it  took  the  Americans  20  seconds  to  come  out, 


DISCUSSION  267 

couple  up  the  hose  and  begin  to  play  the  water  while  it  took  the  Ger- 
mans over  8  minutes  to  prepare  to  fight  the  fire.  Nevertheless  the 
fact  remains  that  the  fire  loss  in  Germany  is  small  compared  with  what 
it  is  in  this  country.  It  is  not  because  they  have  buildings  that  cannot 
be  burned,  because  recently  in  Hamburg  a  number  of  incendiary  fires 
occurred  with  severe  losses.  But  the  principle  of  the  Germans  is  to 
prevent  fire,  not  to  fight  it  after  it  is  started;  while  we  have  gone 
the  limit  in  fighting  fire  after  it  is  started.  We  are  away  behind 
the  rest  of  the  world  in  preventing  fires  before  they  start.  Switzerland 
is  a  country  of  wooden  houses  yet  the  per  capita  fire  loss  there  last  year 
was  only  2  per  cent  of  the  American  per  capita  loss. 

F.  B.  GILBEETH.  There  is  no  doubt  that  standardization  more 
than  any  other  one  thing  will  reduce  the  number  of  fires;  but  let 
it  be  standardization  for  the  prevention  of  fires  rather  than  for  extin- 
guishing them  after  they  are  started.  Fires  are  the  product  of  ignor- 
ance. A  very  small  proportion  of  architects,  and  a  still  smaller  num- 
ber of  engineers,  know  how  to  construct  a  building  that  will  not  burn 
up. 

In  a  paper  on  the  Waste  of  Natural  Eesources  by  Fire,1  Charles 
Whiting  Baker  gave  a  striking  illustration  of  the  annual  loss  not  only 
of  property  but  of  human  life.  He  said : 

The  buildings  consumed,  if  placed  on  lots  of  65  ft.  frontage, 
would  line  both  sides  of  a  street  extending  from  New  York  to  Chicago. 
A  person  journeying  along  this  street  of  desolation  would  pass  in 
every  thousand  feet  a  ruin  from  which  an  injured  person  was  taken. 
At  every  three-quarters  of  a  mile  in  this  journey  he  would  encounter 
the  charred  remains  of  a  human  being  who  had  been  burned  to  death. 

I  have  seen  many  of  the  big  conflagrations  in  this  country :  Toronto, 
Rochester,  Baltimore,  ,San  Francisco  and  Sioux  City.  A  careful  ex- 
amination of  all  these  ruins  shows  that  if  we  tried  to  construct  build- 
ings that  would  burn  up  we  really  could  not  do  a  much  better  job. 
Reports  of  experiments  carried  on  by  Professor  Woolson  in  New  York 
City  during  the  last  ten  years  contain  much  valuable  information 
upon  this  subject. 

We  face  an  entirely  new  situation  today  with  the  advent  of  con- 
crete, which  when  made  with  the  proper  aggregates,  such  as  trap  rock 
and  the  right  kind  of  sand,  is  of  tremendous  assistance  in  resisting 
the  spread  of  fires.  In  fact,  we  are  not  depending  on  any  of  the  old 

1Joint  meeting  of  the  Engineering  Societies  on  the  Conservation  of  Natural 
Resources,  New  York,  March  24,  1909. 


268  DISCUSSION  ON  FIRE  PROTECTION 

types  of  construction  and  fireproofing  schemes  for  preventing  the 
spread  of  fires.  Let  us  have  buildings,  to  begin  with,  that  will  not  aid 
the  spread  of  fire. 

I  suggest  for  the  consideration  of  the  Society  an  exhibit  room 
to  which  engineers,  architects  and  insurance  companies  may  come 
and  satisfy  themselves  that  there  is  not  a  single  thing  in  construc- 
tion today  that  cannot  be  made  better  and  quite  as  cheaply  out  of  ab- 
solutely incombustible  material. 

JAMES  B.  SCOTT.  Education,  it  has  been  said,  should  properly 
begin  with  one's  grandparents,  and  undoubtedly  the  time  to  begin 
fighting  a  fire  is  before  it  begins.  But  granting  that  the  "eugenics''' 
of  fire  fighting  have  been  properly  observed,  there  will  always  remain 
the  possibility  of  accident  or  incendiarism,  giving  rise  to  a  hand-to- 
hand  conflict  with  man's  ancient  enemy.  The  ships  that  can  deliver 
more  shells  and  heavier  shells,  in  a  given  time  and  within  a  given 
area,  and  can  begin  delivery  a  few  minutes  earlier  than  the  enemy,  are 
usually  awarded  the  victory  in  a  modern  naval  engagement.  The 
fire-fighting  system  which  can  deliver  enough  water,  at  a  suitable 
pressure,  just  where  it  is  needed,  and  can  begin  delivery  in  the  fewest 
possible  minutes  after  the  discovery  of  a  dangerous  fire,  is  approach- 
ing the  coveted  100  per  cent  efficiency  in  its  limited  field,  as  distin- 
guished from  the  wider  province  of  fire  prevention. 


No.  1419 

PRESENT  STATUS  OF  THE  LARGE  GAS 
ENGINE  IN  EUROPE 

BY  PROF.  P.  LANGER,  AACHEN,  GERMANY 
Member  of  the  Society 

The  tendency  to  utilize  in  gas  engines  the  enormous  quantities  of 
waste  gases  from  blast  furnaces  had  its  inception  in  Germany  about 
20  years  ago.  The  attempt  was  then  made  to  create  units  of  larger 
power  by  increasing  in  size  the  parts  of  smaller  motors  and  by  using 
a  larger  number  of  cylinders.  The  two-cycle  system  also  seemed  to 
offer  a  suitable  method  of  operation  for  large  engines,  on  account  of 
its  more  efficient  utilization  of  the  mechanism  as  compared  with  the 
single-acting  four-cycle  system.  Full  success  was  not  attained,  how- 
ever, until  about  11  years  ago  when  the  large  gas  engine  was  brought 
to  a  high  state  of  perfection  by  the  Maschinenf abrik  Nuernberg  in  the 
form  of  the  double-acting  four-cycle  type,  with  two  cylinders  ar- 
ranged in  tandem.  It  was  recognized  that  the  principles  on  which  to 
base  the  design  of  large  gas  engines  should  involve  (a)  the  greatest 
possible  accessibility  of  all  parts  exposed  to  the  gases  of  combustion, 
and  (&)  relieving  the  cylinder  wall  of  the  weight  of  the  piston. 

2  These  principles  have  not  only  been  proven  to  be  correct  but 
their  observance  has  been  found  to  be  a  necessary  condition  for  the 
success  of  large  gas  engines. 

3  The  gas  engine  puts  much  higher  demands  upon  the  attendant 
than  any  other  prime  mover.    It  creates  its  own  potential  energy  by 
conversion  of  the  chemically  latent  heat  energy  of  the  gas.     Almost 
any  defect  of  the  machine,  inherent  or  acquired,  which  interferes  with 
the  conversion  of  the  chemical  energy,  acts  destructively  upon  the 
machine,  not  to  mention  its  influence  upon  the  power  output.     The 
simple  consideration  that  gas  is  being  burnt  without  rendering  its 
equivalent  in  power,  leads  to  the  conclusion  that  the  balance  is  being 
transmitted  to  the  cooling  water  under  pressures  and  temperatures  be- 
yond what  are  permissible,  and  that  exhaust  gases  unallowably  hot 


Presented  at  the  Annual  Meeting  1913,  of  THE  AMERICAN  SOCIETY  OP  ME- 
CHANICAL ENGINEERS. 

847 


848  THE  LARGE  GAS  ENGINE  IN  EUROPE 

are  flowing  around  the  exhaust  valves.  In  the  case  of  the  steam 
engine  a  leaky  piston  does  no  further  damage  than  to  increase  the 
steam  consumption.  The  governor  automatically  adjusts  for  a  longer 
cut-off  and  the  engine  pulls  through  as  long  as  the  boiler  furnishes 
sufficient  steam.  With  the  gas  engine,  however,  a  leaky  piston  causes 
ignition  at  the  wrong  time  which  means  a  release  of  heat  energy  at 
a  time  and  place  when  this  energy  can  do  no  useful  work.  A  con- 
tinuation of  the  operation  under  such  conditions  is  not  permissible. 
Any  attempt  to  force  the  operation  would  cause  heavy  damage  to  the 
machine. 

4  It  is  the  duty  of  the  designer  to  face  these  facts  and  to  design 
the  machine  in  such  a  manner  that  it  is  possible  to  give  it  the  careful 
attention  needed  to  prevent  such  disturbances.    Such  attention  cannot 
be  given  when  access  to  such  vital  parts  as  pistons,  stuffing  box  pack- 
ings and  valves  can  be_had  only  after  a  long  and  difficult  job  of 
disassembling.    The  author  knows  of  an  engine  which,  after  six  years 
of  continuous  day  and  night  operation,  showed  only  0.015  in.  wear 
in  the  diameter  of  the  cylinder.    This  success,  although  immediately 
traceable  to  the  careful  attention  this  machine  received,  is  nevertheless 
indirectly  due  to  the  designer  who  made  it  possible  to  give  such  at- 
tention through  the  excellence  of  his  design. 

5  An  instance  of  defective  design  in  this  respect  is  the  case  of  a 
stuffing  box  in  which  it  is  possible  to  replace  the  packing  rings  only 
by  unscrewing  the  joint  between  the  piston  rod  and  crosshead.     The 
packing  rings  must  be  split  and  the  whole  packing  must  be  easily 
removable  in  order  that  a  new  packing  may  be  put  in  during  a 
brief  interruption  of  the  operation.     The  result  of  neglecting  this 
seemingly  minor  point  of  design  is  a  continuation  of  operation  with 
leaky  packings  and  danger  of  warping  the  piston  rods. 

6  A  further  basic  condition  for  uninterrupted  operation  is  pure 
materials,  pure  gas  and  pure  cooling  water. 

7  Operation  with  impure  materials  puts  demands  upon  the  opera- 
tor which  it  is  impossible  to  meet,  except  by  considerable  reduction 
of  the  output  on  account  of  the  long  interruptions  required  for  clean- 
ing.    It  is  evident  that  the  economy  of  the  plant  suffers  materially 
through  reduction  of  the  output,  as  the  proportion  of  the  unproductive 
capital,  the  idle  machinery,  increases. 


P.  LANGEE  849 

REGULATION  OF  LARGE  GAS  ENGINES 

8  The  attempt  to  attain  stratification  of  the  mixture  inside  of  the 
cylinder  has  led  to  very  complicated  valve  gears.     It  was  hoped  that 
a  gas  valve,  which  remained  open  during  only  a  part  of  the  suction 
stroke  would  direct  the  gas  in  such  a  manner  that  a  combustible 
mixture  would  be  present  at  the  point  of  ignition  even  under  the 
lightest  loads,  whi-le  the  balance  of  the  combustion  space  would  be 
filled  with  inert  air.     The  result,  however,  did  not  justify  this  hope. 
Instead  of  stratification  there  was  only  a  bad  mixture  resulting  in 
irregular  and  uneven  operation.    Today  the  hope  of  attaining  stratifi- 
cation can  be  considered  as  being  finally  disposed  of  and  designers 
have  returned  to  the  simple  throttling  valve  gear. 

9  Throttling  of  gas  and  air  simultaneously,  or  in  other  words, 
regulation  of  the  quantity  of  mixture  only,  is  to  be  preferred  to  the 
throttling   of   gas   only,    as   the   former   method   makes   possible    a 
more  certain  control  of  the  power  developed. 

10  Quantity  regulation  will  give  satisfaction  only  if  the  action 
of  the  governor  upon  the  throttle  valve  has  been  given  careful  con- 
sideration.   Present  and  older  designs  that  are  faulty  in  this  respect 
are  frequently  seen.     It  is  wrong  to  let  the  governor  act  in  such  a 
way  that  the  valve  opening  is  proportional  to  the  effective  travel  of 
the  governor  sleeve,  as  the  following  consideration  will  show: 

11  The  result  of  throttling  is  to  reduce  the  quantity  of  mixture 
drawn  into  the  cylinder  during  each  stroke,  on  account  of  the  reduced 
openings  for  gas  and  air.     The  volume  of  the  charge  remains  the 
same,  as  the  cylinder  is  always  completely  filled.    The  density  of  the 
charge  will  become  less  and  correspondingly  its  weight  and  the  amount 
of  energy  supplied. 

12  These  relations  are  shown  in  the  curves  of  Fig.  1.     Starting 
with  a  certain  velocity  C  of  the  mixture  in  the  valve,  which  is  de- 
termined by  the  opening  of  the  valve,  the  curve  shows  the  velocity  as 
a  function  of  the  position  of  the  governor.     This  velocity  can  be 
produced  only  by  a  certain  drop  in  pressure  as  the  mixture  passes  to 
the  cylinder,  so  that  the  law  according  to  which  the  absolute  pressure 
in  the  cylinder  changes  is  also  definitely  determined. 

13  The  density  of  the  charge  is  proportional  to  the  absolute  pres- 
sure and  the  absolute  weight  of  the  charge  of  constant  volume  is 
proportional  to  the  density,  and  so  is  the  amount  of  heat  energy  sup- 
plied.    The  shape  of  this  curve  shows  that  the  lower  part  of  the 


850 


THE  LARGE  GAS  ENGINE  IN  EUROPE 


travel  of  the  governor  sleeve  is  almost  without  influence  and  that  the 
total  regulation  is  limited  to  the  upper  travel. 


Atm.  Line 


-Total  Lift  of  6overnor- 
P*  Absolute  (Suction)  Pressure  in  Cylinder. 
A '  Free  Opening  Area  in  Mixing  Valve. 
C-  Gas-  and  Air- Velocity  through  Mixing  Valve. 

FIG.  1     CURVE  SHOWING  EELATIONS  OF  OPENING  OF  MIXING  VALVE,  UNDER  CON- 
TROL OF  GOVERNOR,  TO  SUCTION  IN  CYLINDER  AND  VELOCITY  THROUGH  VALVE 


1000, 


800 


600 


3. 
2400 


EOO 


-7  Total  Lift  of  Governor > 

FIG.  2    CURVE  SHOWING  EFFECT  OF  PROPER  ADJUSTMENT  OF  GOVERNOR  MECH- 
ANISM TO  OBTAIN  UNIFORM  UTILIZATION  OF  TOTAL  LIFT  OF  VALVE 

14  The  result  of  this  wrong  regulation  is  marked  irregularity  of 
the  indicator  diagrams,  as  the  smallest  motion  of  the  governor  causes 
considerable  changes  in  the  quantity  of  mixture  supplied.  Combustion 


P.    LANGER 


851 


is  irregular,  there  is  tendency  to  backfire,  or  in  one  word,  the  machine 
"does  not  govern/3 

15  The  remedy  is  found  in  changing  the  connection  between  the 
governor  sleeve  and  the  throttling  mechanism  in  a  manner  such  that  in 
the  low  positions  of  the  governor  the  throttling  action  is  more  inten- 
sive than  in,  the  upper  positions.  This  action  can  be  accomplished  in  a 
simple  manner  by  off-setting  the  connecting  link  between  the  governor 
and  the  throttling  valve,  similar  to  the  arrangement  found  in  Corliss 
valve  gears.  This  allows  a  uniform  utilization  of  the  effective  lift  of 
the  governor,  and  consequently  stable  and  quiet  regulation,  without 
any  complication  whatever.  Fig.  2  shows  a  diagram,  characterizing 


FIG.  3     TYPICAL  DESIGN  OF  MIXING  VALVE  FOR  LARGE  GAS  ENGINES 

the  regulation  as  taken  from  an  engine  having  a  properly  designed 
throttling  gear. 

16  Even  the  best  considered  scheme  of  regulation  will  not  avail, 
if  the  proportion  of  mixture,  that  is  the  ratio  of  gas  to  air,  is  not 
properly  controlled.  In  engines  that  have  s'eparate  pumps  for  air 
and  gas,  as  usual  in  two-cycle  machines,  where  therefore,  air  and 
gas  are  furnished  in  measured  quantities,  it  is  a  comparatively  easy 
matter  to  get  the  proper  proportion,  at  least  at  full  load.  Diffi- 
culties are  found,  however,  in  four-cycle  machines,  where  gas  and  air 
are  drawn  in  in  parallel  by  the  working  piston.  In  this  Case  the 
proportion  of  mixture  is  not  readily  controlled,  because  the  quantities 
drawn  in  depend  not  only  on  the  free  opening  of  the  admission  valve. 


852  THE  LARGE  GAS  ENGINE  IN  EUROPE 

but  on  the  product  of  this  opening  area  and  the  velocity  of  flow 
through  it.  Incidental  changes  in  pressure,  due  to  static  or  dynamic 
causes,  may  influence  this  velocity  strongly. 

17  If  we  denote  by  Pg  and  Pa  the  pressure  in  the  gas  and  air 
pipes  respectively,  before  they  reach  the  mixing  chamber  (Fig.  3), 
and  by  Pm  the  pressure  prevailing  at  the  same  time  in  the  mixing 
chamber,  then  Pg  —  Pm  is  the  difference  in  pressure  creating  the 
velocity  of  gas  and  Pa  —  Pm  the  difference  in  pressure  creating  the 
velocity  of  air.  Consequently  velocity  of  gas 


\/ 

=^ 


and  velocity  of  air 


\  /         t  a 
=    ^- 


t  a  ~  * 


If  we  denote  by 

yg   =  specific  weight  of  gas 
ya   =  specific  weight  of  air 
Ae   =  area  of  gas-port 
A&  =  area  of  air-port 

•"  g  ==  Pg  ~  Pm 
H&  =  Pa  —  Pm 

Volume  of  gas  drawn  in 


v/ 

=  Ag  V 


2(7 
Volume  of  air  drawn  in 


Therefore  the  ratio  of  mixture 


ya  K 

Va        Aa  ye        Ha 

18  It  may  be  noted  that  the  difference  in  specific  gravity  must  be 
considered  when  deciding  upon  the  proportions  of  the  ports  for  correct 
mixture  in  engines  that  use  gases  lighter  than  air.  A  disregard  of 


P.    LANGER 


853 


this  fact  leads  to  too  rich  mixtures  and  the  engine  becomes  choked 
with  gas.  The  many  failures  of  engines  working  with  coke  oven  gas 
are  partly  explained  by  wrongly  proportioned  gas  ports.  At  least, 
it  was  found  that  proper  operation  resulted  in  many  cases  from  ma- 
terially reduced  gas  ports. 

19  If,  for  the  sake  of  simplicity,  we  assume  in  the  case  of  blast 
furnace  gas,  the  ratio  of  the  port  areas  as  well  as  the  ratio  of  specific 
gravities,  to  equal  unity ;  and  if  we  assume  the  equation  Hg  =  Ha  ±_  x, 
where  x  denotes  the  difference  in  gas  pressure,  as  compared  with  the 


Inches  of  Water  (X) 

FIG.  4    CURVE  SHOWING  VARIATIONS  IN  EATIO  OF  MIXTURE  OF  GAS  AND  AIR 
WITH  DIFFERING  VELOCITIES  OF  AIR  DRAWN  IN 


air  pressure,  then  we  have  the  very  simple  relation,  for  the  ratio  of 
mixture 


M  =    M+ 


This  equation  shows  what  means  have  to  be  employed  in  order  to  keep 
the  variations  of  the  mixture  within  permissible  limits.  It  shows 
the  necessity  of  keeping  PIa  high,  which  means  that  we  must  work 
with  high  velocities  in  the  mixing  valve,  because  the  larger  the  value 

JM 

of  H  a,  the  smaller  the  value  of  -==—  for  a  given  value  of  x,  and  the 

n& 

smaller  the  variation  of  M  from  the  desired  value  1. 


854  THE  LARGE  GAS  ENGINE  IN  EUROPE 

20  Fig.  4  shows  the  curves  of  M  for  different  velocities  of  intake 
(600,  1000  and  1600  ft.  per  min.).     These  curves  show  that  the  intake 
velocity  in  the  mixing  valve  must  be  at  least  1 000  ft.  per  min.  in  order 
to  avoid  disturbing  variations  of  the  mixture  due  to  accidental  changes 
of  the  gas  pressure.     Practical  experience  fully  confirms  the  correct- 
ness of  this  consideration.    Velocities  of  about  1200  ft.  per  min.  must 
be  considered  as  normal.    In  order  to  avoid  too  intensive  a  throttling 
action  and  consequent  reduction  of  power,  the  piping  and  other  pas- 
sages leading  to  the  mixing  valve  must  be  proportioned  liberally,  so 
that  the  total  drop  in  pressure  is  advantageously  concentrated  within 
the  valve  itself. 

21  The  foregoing  calculations  are  based  upon  the  simplifying  as- 
sumption that  the  flow  into  the  mixing  chamber  takes  place  at  a  uni- 
form rate  and  without  loss. 

22  For  a  long  time  great  difficulties  were  presented  by  the  problem 
of  driving  variable  speed  blowing  engines  by  four-cycle  gas  engines. 
In  most  cases  the  gas  arrives  at  the  mixing  valve  under  a  pressure  of 
several  inches  of  water  above  the  atmosphere,  while  the  pressure  of 
the  air  is  somewhat  less  than  atmospheric.    When  the  machine  is  run 
slower  the  suction  action  of  the  piston  is  reduced  and  the  intake 
velocity  of  the  air  decreases  more  rapidly  than  that  of  the  gas,  until 
finally  it  is  reduced  to  such  an  extent  that  nothing  but  gas  enters  the 
cylinder.    It  is  self-evident  that,  even  before  this  point  is  reached,  the 
engine  will  choke  with  gas  and  will  stop.    A  governor  which  regulates 
the  quality  of  the  mixture  would  only  favor  this  suffocation  of  the 
engine  with  gas.     In  such  cases,  too,  the  conditions  are  improved  by 
intensive  throttling  at  normal  speed. 

CYLINDERS 

23  Improvements  of  design  as  well  as  improvements  in  foundry 
practice  have  reduced  the  breakage  of  cylinders  to  a  point  where  it  is 
now  rather  a  rare  occurrence.     Views  upon  the  most  suitable  shape 
still  differ,  however,  considerably.    While  in  all  other  details  of  large 
gas  engines  standard  designs  have  been  developed,  which  serve  all 
purposes,  the  cylinder  designs  still  vary  considerably.    The  fact  that 
some  designers,  after  careful  experiments,  have  abandoned  the  split 
jacket  cylinder  in  favor  of  the  normal  one-piece  cylinder,  while  others, 
also  after  careful  experiments,  have  gone  in  exactly  the  opposite  di- 
rection, and  split  not  only  the  jacket,  but  also  the  inside  cylinder, 
Fig.  5,  seems  to  show  an  uncertainty  in  judging  the  causes  of  breakage. 
These  differences  in  design,  however,  are  caused  largely  by  fixed  ideas 


P.    LANGER 


855 


of  the  purchasers  whose  special  wishes  are  complied  with  by  clever 
salesmen.  The  one-piece  cylinder  is  just  as.  strong  as  the  split  one. 
The  split  cylinder  has  come  principally  from  the  desire  to  avoid  initial 
stresses  in  the  direction  of  its  axis,  which  put  the  inner  cylinder  under 
tension  on  account  of  the  fact  that  in  casting  it  cools  later  than  the 
rest  of  the  casting.  Besides,  by  casting  the  two  halves  separately,  it 
was  attempted  to  obtain  as  close-grained  a  wall  as  possible  for  the 
combustion  chamber.  Finally,  splitting  the  cylinder  has  the  advantage 
that  customers  who  consider  a  cylinder  liner  the  proper  construction 
can  be  satisfied,  inasmuch  as  the  insertion  of  liners  in  one-piece 
cylinders  presents  some  difficulties,  though  these  are  not  to  be  con- 
sidered insurmountable. 


FIG.  5    DESIGN  OF  SPLIT-JACKET  GAS  ENGINE  CYLINDER  WITH  SPLIT  INSIDE 

CYLINDER 

24  Besides  the  advantage  of  simplicity  and  the  absence  of  the 
danger  of  leakage  in  the  highly  strained  cylinder  joint,  the  one-piece 
cylinder  allows  a  better  transmission  of  the  forces  from  the  cylinder 
to  the  frame.  The  fact  that  one-piece  cylinders  frequently  broke  at 
the  place  indicated  in  Fig.  6,  caused  an  over-estimation  of  the  stresses 
in  the  casting.  Closer  investigation  shows  that  the  breaks  are  caused 
simply  by  making  the  part  between  cylinder  and  flange  too  weak.  The 
wall,  besides  being  too  weak  originally,  is  further  weakened  by  the 
large  number  of  cover  studs  and  the  break  is  further  induced  by  ex- 
cessive tightening  of  these  studs.  This  fault  can  be  remedied  by 
properly  reinforcing  the  point  of  danger  and  by  placing  the  joint 
shoulder  on  the  outside.  As  a  matter  of  fact,  breakage  on  account  of 
strains  in  the  casting  or  from  expansion  due  to  heat,  has  not  occurred 
in  cylinders  that  were  properly  reinforced.  Improvements  in  foundry 
practice  have  undoubtedly  helped  to  avoid  such  breakage. 


856 


THE  LARGE  GAS  ENGINE  IN  EUROPE 


25  While  the  breaks  just  discussed  have  their  origin  in  the  strains 
set  up  by  irregular  cooling  of  the  casting  or  by  irregular  heating  in 
operation,  cracks  of  an  entirely  different  nature  have  been  observed 
on  the  walls  of  the  combustion  chamber.  These  so-called  fire  cracks 
always  start  in  a  place  where  the  transmission  of  heat  to  the  cooling 
water  was  impeded  by  some  cause  or  other  (see  Fig.  7).  The  cause 
of  these  cracks  is  to  be  found  in  the  stresses  produced  by  unequal 
temperatures  within  the  same  wall.  In  the  smooth  and  homogenous 
Avail  the  differences  in  temperature  of  the  different  strata  are  small 
and  the  temperature  of  the  wall  is  comparatively  low,  as  long  as  ac- 
cumulated scale  or  similar  causes  do  not  offer  an  obstacle  to  the 
transmission  of  heat.  When,  however,  the  capacity  of  the  wall  for 
conducting  heat,  or  the  rate  of  transmitting  heat  to  the  cooling  water  is 


FIG.  6    DETAIL  OF  POINT  OF  FREQUENT  BREAKAGE  OF  ONE-PIECE  GAS  ENGINE 

CYLINDERS 

reduced,  there  will  be  an  accumulation  of  heat  which  will  cause  a  con- 
siderable rise  of  temperature  during  the  expansion  and  exhaust  strokes. 
The  material  will  tend  to  expand  according  to  the  average  temperature 
of  the  wall  and  it  will  be  able  to  do  this  without  resistance  because 
it  was  under  tension  on  account  of  the  strain  in  the  casting.  In 
operation,  therefore,  the  strain  will  be  relieved.  On  account  of 
temperature  differences,  however,  in  different  strata  of  the  wall,  there 
will  be  stresses  in  the  wall  itself,  compression  in  the  hotter  zones  and 
tension  in  the  cooler  ones. 

26  This  condition  of  stress  can  be  compared  with  that  existing  in 
a  bar  being  bent  towards  the  inside  of  the  cylinder.  In  the  hotter 
layer  the  expansion  being  resisted  causes  compression  stresses,  and 
in  the  colder  layers  there  will  be  tension  stresses.  As  soon  as  the  cold 
mixture  is  admitted  during  the  next  suction  stroke,  the  surface  of  the 


P.    LANGER 


857 


wall  is  cooled  intensively.  The  inside  layers  of  the  wall  cannot  follow 
rapidly  enough  to  cause  the  establishment  of  settled  conditions  corre- 
sponding to  this  flow  of  heat.  The  mean  temperature  of  the  wall,  and 
consequently  its  average  expansion  can  only  be  affected  very  slightly 
during  the  first  moment  of  internal  cooling  by  the  entering  cold 
mixture.  The  innermost  layer  will  be  under  strong  tension  on  account  \ 
of  the  sudden  cooling.  This  " jumping"  of  the  temperature  acts  upon 
the  material  in  much  the  same  manner  as  sudden  flexure  from  the 
inside  to  the  outside  would.  The  inside  layer  of  the  wall  of  the  com- 
bustion chamber,  therefore,  is  exposed  to  the  same  kind  of  stresses  as 


FIG.  7 


TYPICAL  LOCATIONS  OF  FIRE  CRACKS  IN  PLACES  WHERE  COOLING  is 
IMPEDED 


the  outside  fiber  of  a  bar  that  is  continuously  bent  in  both  directions 
by  blows.  The  stresses  which  occur  under  these  conditions  are  about 
proportional  to  the  difference  in  temperature,  the  coefficient  of  heat 
expansion,  and  the  modulus  of  elasticity,  if,  indeed,  one  can  speak  of 
such  in  the  case  of  cast-iron. 

27  This  is  an  extraordinarily  unfavorable  case  of  strain.  Cases  of 
strain  on  account  of  sudden  changes  of  temperature  are  not  rare,  but 
these  conditions  are  worst  in  the  cylinders  of  gas  engines,  on  account 
of  the  rapid  succession  of  the  changes  in  temperature.  A  mathematical 
deduction  of  these  stresses  is  out  of  the  question  on  account  of  the 
impossibility  of  obtaining  even  halfway  accurate  data  on  the  distri- 


858  THE  LARGE  GAS  ENGINE  IN  EUROPE 

bution  of  temperature  at  any  one  moment  over  the  different  zones  of 
the  wall. 

28  If  we  bear  in  mind,  however,  that  a  difference  in  temperature 
of  200  deg.  fahr.,  when  the  expansion  is  restrained,  corresponds  to  a 
strain  of  about  15,000  Ib.  per  sq.  in.,  we  are  surprised  to  find  that 
cracks  do  not  occur  more  often.    The  occurrence  of  a  crack,  which  in 
the  beginning  is  scarcely  %  in.  deep,  apparently  relieves  the  strain 
to  a  certain  extent  and  only  the  natural  tendency  of  the  cast  material 
to  continue  to  break  together  with  the  external  mechanical  forces 
causes  the  crack  to  open  further.    In  most  cases  drilling  and  calking 
at  the  end  of  the  crack  will  stop  this.     The  timely  discovery  of  the 
crack  is,  however,  rather  difficult,  as  it  is  not  open  after  the  wall  is 
uniformly  cooled. 

29  The  first  step  in  combatting  the  occurrence  of  these  cracks 
must  reduce  their  real  source,  i.  e.,  the  differences  in  temperature,  to 
an  amount  that  is  harmless.    As  the  sudden  changes  of  temperature 
are  caused  by  the  very  nature  of  the  gas  engine  cycle,  these  attempts 
must  be  confined  to  avoiding  all  irregular  ignition  and  slow  com- 
bustion, both  of  which  are  liable  to  increase  the  temperature  of  the 
cycle  beyond  the  normal  as  well  as  the  difference  in  temperature  when 
the  sudden  change  occurs  at  the  beginning  of  the  suction  stroke. 
Furthermore,  it  is  necessary  to  make  the  conductivity  of  the  wall 
uniform  in  order  to  avoid  accumulations  of  heat  in  the  material.    It 
is  therefore  necessary  to  avoid  all  accumulations  of  material.     Pas- 
sages as  shown  at  "X,  Figs.  5  and  7,  are  also  bad.    Here  accumulations 
of  heat  are  the  natural  consequence  of  the  imperfect  conduction  of 
heat  being  directed  towards  a  center,  the  passage  at  the  same  .time 
being  very  much  exposed  to  the  cooling  action  of  the  incoming  air. 
Places  like  these  are  predestined  to  suffer  from  heat  cracks. 

30  The  commonly  used  globe  or  onion-shaped  passages  for  inlet 
and  exhaust  valves  are  therefore  not  suitable,  and  lately  the  form 
shown  in  Fig.  8  is  very  properly  preferred.  Here  the  valves  are  brought 
close  to  the  inner  surface  of  the  cylinder. 

31  In  a  much  more  effective  manner  than  by  measures  of  design, 
can  the  heat  cracks,  and  in  fact  all  cracks  that  occur  in  gas  engine 
cylinders,  be  avoided  by  proper  choice  of  a  material.    The  constant  of 
this  material   (coefficient  of  heat  expansion  multiplied  by  modulus 
of  elasticity),  must  be  less  than  is  the  case  with  cast  iron.    The  less 
the  expansion  from  heat,  which  is  the  real  cause  of  the  strain,  and 
the  more  elastic  the  material,  the  less  the  strain. 


P.    LANGER 


859 


32  Considering  the  enormous  progress  which  metallurgical  science 
has  recorded  during  the  past  few  years,  a  solution  of  this  question  of 
material  should  appear  possible,  and  the  more  so,  as  nickel  steel  alloys 
have  actually  been  made  for  accurate  rules,  in  which  expansion  from 
heat  cannot  be  detected  at  all. 

33  An  investigation  of  the  constant  in  question    (coefficient  of 
heat  expansion  multiplied  by  modulus  of  elasticity)  upon  which  de- 
pends, according  to  the  foregoing,  the  strain  of  the  material  resulting 
from  uneven  temperature,  shows  that  cast  steel  is  not  a  suitable  ma- 
terial for  gas  engine  cylinders.     The  larger  expansion  due  to  heat  as 
compared   with   cast-iron   and   the   very   much   higher   modulus   of 


FIG.  8    EECENT  DESIGN  OF  ONE-PIECE  GAS  ENGINE  CYLINDER  THAT  AVOIDS 
GLOBE-SHAPED  PASSAGES  TO  VALVES 

elasticity  causes  increased  stresses,  while  the  strength  of  cast  steel  is 
not  proportionately  greater.    Experience  confirms  this  conclusion. 

ON  INCREASING  THE  OUTPUT  OF  LARGE  GAS  ENGINES 

34  The  principal  task  upon  which  the  gas  engineer  is  laboring 
incessantly,  besides  that  of  increasing  the  reliability  of  the  machine, 
is  that  of  making  it  cheaper,  partly  by  simplifying  its  construction, 
partly  by  increasing  its  output.  At  present  it  can  hardly  be  imagined 
that  the  gas  engine  can  be  made  cheaper  by  making  its  construction 
simpler,  now  that  the  complicated  valve  gears  have  disappeared.  Ke- 
duction  of  weight  is  not  to  be  recommended.  Until  recently  experi- 
ence has  demanded  a  continuous  increase  of  engine  weights.  Economy 


860  THE  LARGE  GAS  ENGINE  IN  EUROPE 

* 

in  material  would  reduce  reliability  and  length  of  life  of  the  machine. 
The  mechanism  has  been  developed  into  standard  designs,  so  that  in 
this  detail  there  is  nothing  to  be  saved. 

35  Somewhat  better  prospects  seem  to  be  opened  by  the  attempt 
to  reduce  the  cost  by  increasing  the  output  of  the  machine  of  a  given 
size.    Let  us  consider  the  equation  for  the  power  of  the  machine 

1 
W  =  —  HVytiviit 

A 
in  which 

V    =  the  swept  volume    (the   factor  which   determines   the 

absolute  cost) 

H  =  the  heating  value  of  the  mixture 
7^v  =  the  volumetric  efficiency 
rji   =  the  total  efficiency 

7     =  the  number  of  suction  strokes  per  second 
A    =  the  mechanical  equivalent  of  heat 

36  An  increase  of  7  by  increasing  the  number  of  revolutions  per 
minute,  .is  not  practicable,  at  least  not  with  less  combustible  gases 
such  (as  blast  furnace  gases.     The  reliability  of  the  machines  would 
be  lessened,  not  even  considering  the  fact  that  the  time  available  for 
the  combustion  of  the  mixture  is  too  short  and  that  therefore  the 
losses  on  account  of  incomplete  combustion  would  become  too  large. 
A  comparison  of  the  results  of  operation  of  gas  operated  blowing 
engines,  which  run  relatively  slow,   and  engines  driving  dynamos, 
proves  that  the  former  require  considerably  less  repairs  than  the  latter. 
Increasing  the  number  of  revolutions  would  increase  the  idle  time  on 
account  of  repairs,  and  a  gain  in  output  can  hardly  be  expected. 

37  The  heating  value  of  the  mixture  H,  is  also  determined  by  the 
minimum  excess  of  air  necessary  for  complete  combustion,  and  there 
remain  only  the  two  factors  of  volumetric  and  total  efficiency.    It  is 
conceivable  that  the  total  efficiency  might  be  increased  by  increasing 
the  thermal  efficiency  of  the  process.     This,  however,  is  dependent 
upon  increase  of  the  pressure  and  for  this  reason  such  a  possibility 
must  be  eliminated.     The  volumetric  efficiency  can  be  increased  in 
two  ways;  by  cooling  the  charge  and  by  increasing  the  pressure  of 
the  charge.    The  first  method  was  proposed  some  time  ago.    It  is  not 
being  adopted  because  in  most  cases  the  cooling  water  is  warmer  than 
the  atmosphere  and  the  incoming  gas.     Besides,  a  large  gain  cannot 
be  expected,  as  decreasing  the  temperature  of  the  charge  10  deg.  fahr. 
could  only  increase  the  output  about  2  per  cent. 


P.    LANGER  861 

38  The  other  method  for  increasing  the  output,  which  lately  has 
attracted  renewed  interest,  consists  in  increasing  the  pressure  of  the 
charge  and  simultaneous  scavenging  of  the  exhaust  gases.     In  this 
manner  a  given  suction  volume  of  an  engine  can  accommodate  a 
larger  weight  of  charge  and  greater  output  of  power  can  be  attained. 

39  The  original  purpose  of  this  method,  which  has  been  known  in 
England  for  many  years,  was  the  avoidance  of  pre-ignition  by  scaveng- 
ing the  cylinder  of  what  remained  of  the  hot  exhaust  gases.    It  is  the 
competition  into  which  the  gas  engine  has  lately  had  to  enter  with  the 
steam  turbine,  that  has  brought  to  the  front  the  possibility  of  increased 
power  output  and  consequently  lower  cost  of  the  machine  per  unit  of 
power. 

40  The  simplest  method  of  realizing  the  scheme  of  scavenging 
and  charging  consists  in  closing  the  exhaust  valve  late  and  opening 
the  inlet  valve  early.     The  time  during  which  both  valves  are  open 
is  used  for  scavenging.     In  order  surely  to  avoid  loss  of  gas,  the 
charging  with  gas  is  only  commenced  after  the  exhaust  valve  is  closed. 
At  the  end  of  the  suction  stroke  the  mixing  chamber  must  be  cleansed 
of  combustible  mixture  by  scavenging   (rinsing)   with  pure  air,  as 
otherwise  backfires  would  occur  at  the  beginning  of  the  next  scaveng- 
ing period.    Gas  and  air  are  brought  to  the  machine  under  a  pressure 
of  about  3  Ib.  per  sq.  in.  gage.    On  account  of  this  increased  pressure 
the  weight  of  the  charge  is  about  20  per  cent  greater  than  that  of  the 
normal  method.     Scavenging  the  combustion  chamber  also  furnishes 
further  space  for  fresh  mixture.     Experiments  have  shown  a  mean 
effective  pressure  of  about  100  Ib.  per  sq.  in.    In  continuous  operation, 
in  so  far  as  we  can  speak  of  such  in  experiments,  mean  effective  pres- 
sures of  85  Ib.  per  sq.  in.  can  be  reached. 

41  Undoubtedly   such  results  present  much  that   is   attractive, 
especially  as  the  output  can  still  be  increased  by  further  increasing 
the  pressure,  and  as  this  would  give  to  the  gas  engine  the  capacity 
for  overloads  which  heretofore  it  did  not  possess  in  the  same  sense 
as  steam  engines  do.    Experiments  have  also  proved  that  these  over- 
loads can  be  had  without  an  increase  of  the  maximum  pressure.    This 
is  done  by  reducing  the  compression. 

42  In  spite  of  the  lower  compression  the  heat  consumption  per  unit 
of  power  was  not  increased.  It  seems  that  this  result  is  explained  first 
by  better  combustion  of  the  charge  which  is  not  contaminated  by  the 
remains  of  the  exhaust  gases,  and  secondly  by  a  decreased  percentage  of 
loss  in  the  cooling  water.    The  predominating  influence  can  only  be 
found  by  means  of  carefully  measured  heat  balances  which  at  present 


862  THE  LARGE  GAS  ENGINE  IN  EUROPE 

are  not  available.  The  increased  temperature  of  the  cylinder  walls, 
which  has  been  found  thermo-electrically,  has  caused  objections 
against  continued  operation  with  scavenging  and  forced  charge.  A 
certain  justification  cannot  be  denied  to  these  objections.  The  de- 
crease of  continuous  loads  is  the  main  factor  that  has  contributed  to 
overcome  the  difficulties  of  operation.  To  endanger  regular  operation 
by  increasing  the  mean  effective  pressure  must  appear  to  be  a  danger- 
ous experiment  in  just  such  cases  where  the  equipment  is  insufficient 
and  an  increase  is  highly  desirable.  The  disposition  on  the  part  of 
operating  engineers  to  await  developments,  is  easy  to  understand. 
The  present  satisfactory  operation,  which  is  the  result  of  years  of 
experience,  is  making  these  engineers  justly  conservative. 

43  The  danger  is  to  be  found  in  the  fact  that  the  increase  of 
output  on  one  hand  is  offset  by  a  decrease  on  the  other  hand  on  ac- 
count of  the  more  frequent  shutdowns  for  repairs.     Besides  these 
questions,  which  can  only  be  solved  by  several  years  of  experience, 
there  are  other  difficulties  in  the  constructive  realization  of  this  idea 
of  increased  output  which  have  to  be  solved  before  it  is  proved  to  be 
practicable  in  sustained  operation.    In  one  word,  there  are  many  nuts 
to  be  cracked,  before  we  can  think  of  a  practicable  increase  of  the 
power  output  of  four-cycle  engines  by  means  of  scavenging  and  forced 
charge. 

IMPKOVING   GAS   ENGINE   HEAT   ECONOMY 

44  The  endless   desire   of  gas   engine  builders   to   improve  the 
economy  of  the  gas  engine,  has  lately  brought  to  the  front  interest 
in  the  utilization  of  waste  heat.     According  to  experience,  a  blast 
furnace  gas  engine  dynamo  consumes  in  continuous  service  on  the 
average  about   16,000   B.t.u.   per  kw-hr.     Of  this   amount  of  heat 
only  3412  B.t.u.  are  converted  into  electrical  energy.    Of  the  balance, 
12,588  B.t.u.,  only  the  mechanical,  electrical,  and  radiation  losses  have 
to  be  regarded  as  unredeemable,  as  well  as  the  energy  contained  in  the 
unburned  gases.     The  heat  in  the  cooling  water,  about  4800  B.t.u., 
and  that  in  the  exhaust,  about  5200  B.t.u.  per  kw-hr.,  is,  however, 
available  for  a  more  or  less  perfect  further  utilization.     The  high 
temperature  of  the  exhaust,  about  880  deg.  fahr.,  measured  at  the 
exhaust  flange,  makes  possible  its  immediate  use  for  the  generation  of 
steam  in  boilers,  which  have  to  be  placed  as  closely  as  possible  to  the 
exhaust  chamber.    As  a  matter  of  fact,  it  is  possible  to  obtain  about 
2  Ib.  of  high-pressure  steam  per  kw-hr.  of  the  gas  engine. 


P.    LANGER  863 

45  The  utilization  of  the  heat  in  the  cooling  water  is  not  possible 
as  directly  as  this.     The  further  use  of  this  heat  for  power  purposes 
means  the  generation  of  steam  and  this  requires  a  considerably  higher 
temperature  of  the  cooling  water  than  that  customary  today  in  large 
gas  engines.     Semmler  suggested  as  long  ago  as  ten  years,  that  gas 
engine  cylinders  be  cooled  with  water  hotter  than  212  deg.  fahr.,  and 
that  this  water  be  put  under  pressure  in  order  to  avoid  the  generation 
of  steam  in  the  jacket.     Evaporation  commences  only  outside  of  the 
jacket,  when  the  superheated  water  is  conducted  through  a  throttle 
valve  into  a  steam  drum.    It  may  be  easily  understood  that  this  "hot 
cooling"  scheme  has  been  regarded  rather  skeptically  for  a  long  time. 
About  a  year  ago  it  was  decided  at  the  Eombacher  Huetten  Werke  to 
try  Semmler's  cooling  method  on  an  800-kw.  tandem  engine.     The 
results  in  operation,  which  are  available  today,  are  entirely  favorable. 
The  hot  jacket  not  only  did  not  hurt  the  cylinder,  but  it  caused  ap- 
parently a  softer  and  more  quiet  operation  of  the  machine. 

46  The  use  of  distilled  water  in  a  closed  cycle  like  .Semmler's,  the 
considerably  higher  temperature  of  the  outer  cylinder  wall,  which 
causes  nearly  equal  average  temperatures  of  the  inner  and  outer 
cylinder  walls,  are  surely  advantages  which,  if  the  favorable  experi- 
ences last,  merit  more  consideration  than  the  recovery  of  waste  heat. 
The  amount  produced  is  in  the  case  of  the  engine  mentioned,  about 
0.5  kg.  of  steam  of  low  pressure  per  kw-hr.    There  is  no  doubt  that 
this  figure  can  be  very  much  improved  by  designing  the  cylinders 
more  suitably  for  this  purpose,  by  careful  insulation  and  by  connecting 
the  cooling  water  from  the  piston  with  this  system,  which  heretofore 
has  not  been  done. 

47  The  results  achieved  in  recovery  of  waste  heat  will  be  of  differ- 
ent practical  value  for  different  types  of  blast  furnace  plants.    Where 
there  is  a  steam  plant  in  addition  to  gas  plants,  it  would  be  advan- 
tageous to  shut  down  some  of  the  boilers  and  substitute  steam  from 
the  waste  heat  boilers  by  connecting  them  to  the  steam  mains,  because 
this  steam  can  be  produced  almost  without  cost  for  attendance  and 
for  fuel,  and  therefore,  as  cheaply  as  is  possible. 

GAS   ENGINE   VS.    STEAM   TUEBINE 

48  In  conclusion  it  may  be  well  to  touch  in  a  few  words,  upon 
the   competition   between  the  gas   engine   and   the   steam   turbine, 
which  lately  has    become  very  keen  in  Germany  as  well  as  in  the 
United  States.    The  steam  turbine  has  doubtless  made  much  progress 


864  THE  LARGE  GAS  ENGINE  IN  EUROPE 

during  the  last  few  years.  In  its  perfected  form  in  which  we  know  it 
today,  it  is  a  thoroughly  reliable  machine.  Its  overload  capacity,  with 
nearly  constant  steam  consumption  per  power  unit,  is  limited  by  its 
accessories,  as  boiler  and  condenser.  In  addition,  there  is  its-  principal 
advantage  of  lower  first  cost  as  compared  with  the  gas  engine.  Its 
disadvantage  is  the  higher  consumption  of  heat  per  unit  of  power. 
The  gas  engine  produces  approximately  twice  the  amount  of  energy 
from  a  given  amount  of  heat,  and  is  therefore,  superior  as  a  fuel 
saver  from  the  economic  point  of  view.  To  the  business  man,  how- 
ever, the  question  of  lower  first  cost  often  appeals  more  strongly.  The 
favorable  balance  sheet  of  the  current  year  pleases  him  better  than  the 
quiet  satisfaction  in  the  knowledge  that  he  has  saved  valuable 
treasures  of  fuel  for  his  great-grandchildren.  But  even  from  this 
standpoint  the  gas  engine  will  be  victorious  over  the  steam  turbine 
in  cases  where  the  available  waste  gases  are  not  so  abundant  that  their 
combustion  under  steam  boilers  would  suffice  to  satisfy  the  existing 
requirements  for  electrical  energy.  Whether  and  to  what  extent  these 
conditions  will  be  changed  by  the  new  method  of  surface  combustion, 
is  a  matter  which  the  future  will  show. 

DISCUSSION 

H.  J.  K.  FREYN.  Professor  Langer  devotes  a  considerable  portion 
of  his  paper  to  the  question  of  regulation  of  large  gas  engines  and  he 
points  out  in  a  very  able  and  clear  manner  that  of  the  two  prevalent 
systems  of  regulation  of  gas  engines,  namely:  by  stratification  of  the 
mixture  and  constant  compression  versus  throttling  of  gas  and  air 
and  variable  compression,  the  latter  method  has  proved  its  superi- 
ority in  every  instance  and  from  every  point  of  view. 

I  can  but  heartily  endorse  every  statement  made  by  Professor 
Langer  and  while  in  my  earlier  career  I  favored  the  stratification 
method,  I  changed  my  mind  many  years  ago  as  a  result  of  practical 
experience  with  engines  regulated  on  both  systems. 

Abroad,  the  leading  gas  engine  manufacturers  have  for  a  con- 
siderable length  of  time  adhered  to  the  stratification  principle,  al- 
though choosing'  the  more  rational  form  of  attempting  to  obtain 
stratification  by  arranging  their  valve  gear  in  such  a  manner  that  a 
certain  quantity  of  pure  air  always  folloived  the  mixture. 

In  this  system,  therefore,  only  one  chance  for  diffusion  between 
gas  mixture  and  pure  air  exists,  with  the  result  that  operation  at 
fractional  load  was  reasonably  satisfactory  because  the  danger  of 


DISCUSSION  BY  H.  J.  K.  FREYN  865 

formation  of  a  bad  mixture  during  the  suction  and  compression  strokes 
was  not  as  great  as  it  is  in  the  system  where  a  variable  quantity  of 
mixture  is  "sandwiched"  between  two  layers  of  pure  air,  causing 
diffusion  in  two  planes,  as  it  were,  on  either  side  of  the  mixture. 

It  has  been  my  experience  that  gas  engines  operating  on  the  so- 
called  stratification  principle,  while  giving  excellent  results  from  full 
load  to  approximately  half  load,  are  not  capable  of  maintaining  regu- 
lar ignition  upon  all  piston  faces  as  soon  as  the  load  drops  below 
approximately  50  per  cent  of  the  rated  capacity. 

The  influence  of  this  phenomenon  upon  regularity  of  operation, 
especially  if  alternating-current  generators  driven  by  such  engines 
have  to  be  operated  in  parallel,  is  very  marked  and  it  will  be 
found  that  such  power  plants  usually  show  excessive  cross  currents 
and  "swinging  on  the  line"  at  light  load.  This  is  not  the  case  with 
engines  regulated  on  the  principle  of  variable  compression  and  con- 
stant mixture,  and  especially  with  those  where  gas  and  air  are  throt- 
tled during  the  whole  suction  stroke. 

Professor  Langer  has  very  ably  and  comprehensively  proved  along 
theoretical  lines  why  this  should  be  so,  and  he  points  out  especially 
what  provision  must  be  made  in  the  governor  gearing  to  bring  about 
the  desired  results,  not  only  at  full  load  but  also  at  fractional  load. 

The  point  of  "drowning"  of  gas  engines  in  gas,  raised  by  the 
author,  is  very  well  taken.  Gas  blowing  engines  which  have  to  be 
operated  at  times  at  reduced  speed  are  particularly  susceptible  to 
drowning.  Gas  blowing  engines  regulated  on  the  principle  of  con- 
stant mixture  and  variable  compression  are  better  suited  for  slow 
speed  operation,  as  was  proven  in  many  instances  in  Europe  where 
large  gas  blowing  engines  could  be  operated  for  one  hour  at  a  speed 
of  19  r.p.m.  with  full  pressure  of  15  Ib.  on  the  blowing  cylinder. 

Without  a  single  exception,  German  gas  engine  manufacturers 
several  years  ago  abandoned  the  stratification  method  of  regulation 
and  a  large  majority  have  adopted  the  so-called  "combination  system," 
making  use  of  the  simplest  method  imaginable  for  throttling  of  air 
and  gas,  viz.,  by  the  application  of  so-called  butterfly -valves  as  throt- 
tling and  regulating  organs. 

These  engines  are  regulated  in  the  following  manner.  From  full 
load  down,  the  governor  acts  first  only  upon  the  gas  dampers 
with  decreasing  load,  while  the  air  dampers  remain  in  their  original 
position.  Below  about  60  to  70  per  cent  of  rated  load,  the  governor 
begins,  through  a  toggle  motion,  to  act  upon  the  air  butterflies  as 


866  THE  LARGE  GAS  ENGINE  IN  EUROPE 

well.  The  toggle  effect  is  so  arranged  that  with  further  decreasing 
load,  the  air  dampers  act  more  quickly  than  the  gas  dampers,  so  that 
below  a  certain  fractional  load  a  perfectly  constant  mixture  is 
admitted. 

It  will  be  seen  that  this  combination  method  of  regulation  com- 
bines the  advantages  of  both  stratification  and  constant  mixture  regu- 
lating methods ;  at  the  heavier  loads,  practically  constant  compression 
is  obtained,  while  at  the  lighter  loads  governing  is  performed  on  the 
constant  mixture  principle. 

With  reference  to  the  subject  of  gas  cylinders,  I  believe  that  Pro- 
fessor Langer's  excellent  exposition  of  the  relative  merits  of  cast  iron 
and  cast  steel  and  of  the  one-piece  vs.  the  split  gas  cylinder  deserves 
the  careful  attention  of  both  gas  engine  builders  and  users.  Pro- 
fessor Langer's  discussion  of  this  question  is  very  timely,  because  in 
this  country  the  battle  between  the  advocates  of  the  one  and  those  in 
favor  of  the  other  is  still  waging. 

I  have  had  an  opportunity  of  studying  these  questions  in  detail 
during  the  last  few  years  and  I  have  come  to  the  conclusion  that 
Professor  Langer  is  unquestionably  right  in  his  preference  for  one- 
piece  cast-iron  gas  cylinders  fitted  with  hard  cast-iron  liners.  Earlier 
difficulties  with  cracking  of  gas  cylinders  have  naturally  led  manu- 
facturers to  look  for  a  building  material  which  could  stand  up  better 
under  the  strains  and  stresses  imposed  by  mechanical  forces  and  tem- 
perature variations.  In  Europe  cast-steel  cylinders  were  tried  several 
years  ago  with  the  result  that  breaks  occurred  after  a  much  shorter 
time  of  operation  than  when  cast-iron  cylinders  were  used.  I  believe 
that  a  similar  experience  was  had  in  this  country. 

Cast-iron  cylinders  in  one  piece  can  be  made  so  perfect  today  that 
they  will  stand  up  very  well.  At  the  gas  engine  power  plant  at  Gary, 
140  one-piece  cast-iron  gas  cylinders  are  in  operation,  68  of  which 
have  been  in  service  nearly  five  years.  Of  all  these  cylinders  only  one 
had  to  be  actually  replaced  by  a  new  one,  although  at  the  time  of 
installation  of  these  particular  engines,  the  art  had  not  progressed  as 
far  as  it  has  today.  It  is  true  that  a  number  of  these  cylinders  show 
fire  cracks  and  breaks  in  the  counterbore,  but  repairs  have  been  made 
and  the  cylinders  are  still  in  perfectly  satisfactory  operation. 

One  of  the  most  important  points  to  which  by  far  too  little  at- 
tention is  paid,  especially  in  this  country,  is  the  question  of  the  use 
of  suitable  cooling  water.  Very  interesting  experiments  were  made 
abroad  to  determine  the  effect  of  the  accumulation  of  scale  on  the 


DISCUSSION  BY  H.  J.  K.  FREYN  867 

cylinder  walls  and  it  was  found  that  the  average  temperature  of  these 
walls  increased  at  an  amazing  rate  with  seemingly  unimportant  de- 
posits of  scale.  I  know  of  at  least  one  installation  where  thermometers 
are  inserted  permanently  in  the  inner  cylinder  walls  reaching  to 
within  14  in.  of  the  cylinder  bore.  The  operator  is  supposed  to  watch 
these  thermometers  which,  ,after  the  cylinder  jackets  have  been 
thoroughly  cleaned  with  wire  brushes  and  weak  acid  solutions,  show 
a  gradual  rise  of  temperature  while  operation  continues.  As  soon  as 
the  thermometers  show  a  temperature  of  125  deg.  cent,  the  engine 
is  shut  down  and  the  cylinder  walls  are  again  carefully  scrubbed  and 
cleaned.  In  this  particular  instance  the  cracking  and  breaking  of 
gas  cylinders  which  had  become  a  nuisance  on  account  of  its  frequency, 
was  entirely  stopped. 

Professor  Langer  has  elaborated  considerably  on  the  question  of 
the  increase  of  output  of  large  gas  engines  and  improvements  in  gas 
engine  economy.  I  have  studied  the  latest  attempts  of  European 
gas  engine  manufacturers  to  obtain  an  overload  capacity  of  four- 
cycle gas  engines  by  using  the  so-called  scavenging  and  surcharging 
method.  I  have  seen  several  installations  abroad  equipped  with  this 
system  and  I  am  familiar  with  tests  made  by  Ehrhardt  &  Sehmer  on 
engines  furnished  by  them.  They  show  that  in  spite  of  a  material 
increase  in  mean  effective  pressure  amounting  to  £5  to  35  per  cent, 
no  increase  occurs  in  the  initial  pressure  nor  in  the  average  tempera- 
ture of  the  gas  cylinders  and  other  gas  engine  parts  exposed  to  the 
high  temperatures  of  combustion.  This  firm  is  prepared  to  give 
guarantees  regarding  the  heat  consumption  of  engines  equipped  with 
the  scavenging  and  surcharging  system  which  are  not  any  lower  than 
those  usually  given  for  ordinary  four-cycle  engines  of  equal  capacity. 

I  cannot  agree  with  Professor  Langer's  statement  that  engines 
operated  on  this  principle  are  subject  to  a  greater  wear  and  tear  than 
ordinary  gas  engines;  the  stresses  and  strains  which  the  running 
gear  and  other  engine  parts  sustain  are  due  primarily  to  the  initial 
pressure  and  not  to  the  mean  effective  pressure.  If  we  consider  the 
main  bearings,  for  instance,  it  will  easily  be  seen  that  such  a  bearing 
will  give  no  trouble  as  long  as  a  film  of  oil  can  be  maintained  between 
bearing  shell  and  shaft.  The  maintenance  of  such  a  film  depends 
upon  the  amount  of  pressure  per  square  inch  and  not  upon  its  dura- 
tion; with  lower  initial  pressure  and  higher  mean  effective  pressure, 
therefore,  these  main  bearings  must  give  at  least  as  good  satisfaction 
as  they  are  giving  in  ordinary  four-cycle  engines.  As  a  matter  of 


868  THE  LARGE  GAS  ENGINE  IN  EUROPE 

fact,  the  dimensions  of  pins,  bearings  etc.,  of  scavenged  and  surcharged 
engines  have  not  been  increased  beyond  those  customary  in  ordinary 
non-scavenged  engines. 

The  question  of  utilization  of  the  exhaust  heat  of  gas  engines  has 
had  practically  no  attention  in  this  country,  and  yet  it  is  such  an 
excellent  and  cheap  means  of  increasing  the  usefulness  of  the  gas 
engine  and  the  financial  returns  from  its  application.  I  wish  to  refer 
in  this  connection  to  one  of  the  best  papers  on  the  subject,  which  was 
read  by  Leon  Greiner  before  the  Liege  Engineering  Society  about  a 
year  ago.  Practical  results  are  given  which  were  obtained  with  an 
installation  of  such  boilers  in  connection  with  blast  furnace  gas 
engines  at  the  John  Cockerill  Works  of  Seraing,  Belgium. 

Referring  to  the  competition  between  gas  engines  and  steam  tur- 
bines, I  wish  to  call  attention  to  my  paper  read  before  the  American 
Iron  and  Steel  Institute's  meeting  of  last  May,  which  is  devoted  ex- 
clusively to  this  subject  and  which  proves  with  the  aid  of  cost  figures 
obtained  in  actual,  commercial  operation  of  large  gas  engine  power 
stations  in  this  country  that  gas  engines  operated  on  so-called  "waste" 
industrial  gases — an  unfortunate  misnomer  which  should  be  abolished 
as  quickly  as  possible — are  superior  in  commercial  economy  to  any 
other  known  method  of  producing  power. 

P.  Z.  NEDDEN  said  that  the  present  status  of  the  large  gas  engine, 
both  in  Europe  and  in  this  country,  is  perhaps  more  considerably 
influenced  by  the  introduction  of  surface-combustion  boilers  than 
implied  in  the  paper.  In  this  country  we  have  very  largely  the  use 
of  natural  gas,  especially  in  the  Pittsburgh  district,  which  is  very 
suitable  for  being  used  under  Schnabel-Bone  surface  combustion 
boilers.  One  of  these  installed  at  -the  Shinningroove  Iron  Works,  in 
England,  is  claimed  to  have  given  an  efficiency  of  nearly  90  per  cent, 
as  compared  with  the  efficiency  of  the  ordinary  boiler,  which  ranges 
from  6<5  to  70  per  cent.  That  would  mean  that  with  the  surface- 
combustion  boiler  the  gases  available  in  the  Pittsburgh  district  would 
be  able  to  produce  one-third  more  power  than  at  present.  In  other 
words,  the  cost  of  energy  would  in  that  district  be  reduced  by  about 
20  per  cent. 

A  great  deal  is  said  about  the  advantages  of  the  Schnabel-Bone 
boiler  which  are  naturally  claimed  by  those  interested  in  its  intro- 
duction. Professor  Langer's  experiences  with  it  would  be  of  interest, 
if  he  would  give  some  account  of  them. 


DISCUSSION  869 

To  make  his  questions  more  specific,  he  said  he  would  ask  Professor 
Langer  if  it  was  true  that  the  efficiency  of  the  Schnabel-Bone  boilers 
actually  exceeded  that  of  the  ordinary  boiler  by  about  25  per  cent, 
and  if  that  boiler  was  reliable  in  service1;  also  if  the  utilization  of 
the  heat  of  waste  gases  in  the  gas  engine  was  possible  by  the  Schnabel- 
Bone  boiler? 

E.  H.  FERNALD.  At  a  central  plant  in  this  country,  built  to  utilize 
low-grade  fuels  at  the  mines,  I  ventured  to  criticise  the  fact  that  a 
steam  plant  had  been  constructed  instead  of  a  gas  plant.  The  vice- 
president  of  the  company  said  that  he  had  wanted  to  put  in  a  gas 
plant,  but  was  forced  to  put  in  steam  as  he  found  no  large  gas  pro- 
ducer units  that  would  be  available  and  satisfactory  for  an  installation 
of  the  size  contemplated.  In  other  words,  it  seems  to  be  a  question  ot 
the  size  of  the  unit  which  is  deferring  the  installation  of  plants  of 
100,000  to  250,000  h.p.  directly  at  the  mines.  I  would,  therefore, 
like  to  hear  from  Professor  Langer  his  opinion  regarding  the  possible 
size  of  the  large  gas  engine  of  the  near  future.  The  question,  of 
course,  arises  as  to  what  is  a  large  gas  engine.  In  1900  a  500-h.p. 
engine  was  considered  large.  At  the  present  time  we  have  5000-h.p. 
units.  What  is  to  be  the  large  gas  engine  10  years  from  now?  The 
reciprocating  steam  engine  was  slow  in  developing.  The  steam  turbine 
developed  more  rapidly  than  the  reciprocating  steam  engine. 

All  are  familiar  with  the  relic  in  the  yard  of  the  General  Electric 
Company  at  Schenectady — a  5000-h.p.  unit  which  was  one  of  the 
early  turbines  of  this  country.  This  was  followed  by  an  8000-h.p. 
turbine  and  later  by  a  14,000-h.p.  unit,  and  I  understand  that  an 
order  has  recently  been  placed  for  a  single  unit  of  30,000  or  35,000-kw. 
capacity.  This  steam  turbine  development  has  been  very  rapid. 

If  we  are  to  install  large  central  plants  at  the  mines  and  develop 
electric  current  for  long  distance  transmission  we  must  have  large  gas 
engine  units  if  producer  gas  is  to  compete  with  steam.  A  gas 
producer  of  3000  to  4000-h.p.  capacity  in  a  single  shell  has  recently 
been  installed.  The  construction  of  the  plant  is  so  simple  that  the 
cost  of  manufacture  should  be  low.  If  this  producer  meets  the  demand 
and  proves  to  be  a  commercial  proposition,  there  is  a  possibility  of 
developing  units  of  not  less  than  10,000  h.p.  in  a  single  shell  (since 
these  comments  were  made  I  understand  that  a  unit  of  75  tons 

'This  question  is  very  fully  answered  by  G.  Neumann's  article,  an  extract 
of  which  appeared  in  The  Journal,  Am.Soc.M.E.,  January  1914,  Foreign  Ee- 
view  Section,  p.  09,  etc. 


870  THE  LARGE  GAS  ENGINE  IN  EUROPE 

capacity  per  24  hours  has  been  ordered),  but  gas  engine  units  of  a 
size  to  compete  with  large  steam  turbines  are  slow  in  developing. 
This  central  station  at  the  mines  is  not  pure  theory.  The  few  installa- 
tions that  have  been  made  at  the  mines  have  attracted  the  attention 
of  engineers  and  I  understand  that  one  of  the  large  coal  companies 
of  this  country  is  at  the  present  time  considering  the  installation  of 
such  a  plant  for  the  utilization  of  mine  refuse.  I  was  told  recently 
that  representatives  of  this  company  are  in  Europe  seeking  informa- 
tion relating  to  large  by-product  gas  plants.  I  have  also  been  told 
that  the  producer-gas  interests  are  also  alive  to  the  situation  and 
have  sent  representatives  abroad  within  the  past  few  weeks  to  study 
the  question  of  large  units.  These  large  units  seem  essential  if  we 
are  to  utilize  our  fuel  resources  to  the  best  advantage.  I  trust  that 
Professor  Langer  can  give  us  some  definite  information  regarding 
the  future  of  the  large  gas  engine  unit. 

F.  ,S.  GILLEE.  With  reference  to  the  point  brought  up  about 
having  gas-driven  electric  plants  at  the  coal  mines,  I  would  like  to 
ask  whether  gas  engine  sets,  in  their  largest  sizes,  could  compete  with 
steam  turbine  sets,  in  their  largest  sizes,  in  the  matter  of  cost  of 
production  and  convenience  of  operation. 

It  is  not  easy  to  understand  just  what  is  meant  by  the  author's 
statement  that  the  gas  engine  is  vastly  superior  as  a  fuel  saver  from 
the  economic  point  of  view.  A  concern  handling  a  large  power  pro- 
duction undertaking  does  not  consider  either  cost  of  fuel  or  first  cost, 
except  in  their  relations  to  the  total  cost  of  production.  Undoubtedly 
the  cost  of  fuel  is  a  very  important  item  in  this  total  cost,  but  I  believe 
that  practically  all  of  the  other  items,  such  as  depreciation,  repairs, 
rents,  taxes,  insurance,  interest  on  investments,  etc.,  are  higher  for 
gas  plants  than  for  steam  plants,  and  that  together  they  usually 
constitute  a  greater  argument  against  the  gas  engine  sets  than  the 
high  heat  efficiency  does  for  them.  I  have  lately  visited  many  large 
steam-driven  and  water- driven  electric  generating  plants,  and  also  the 
large  gas-driven  plant  at  Gary.  At  this  last  place,  I  could  not  help 
being  struck  by  the  great  size  of  the  generating  sets  in  comparison 
with  the  sizes  of  corresponding  turbine  sets,  the  enormous  foundations 
and  buildings  required  by  them,  and  the  obvious  need  of  a  large 
staff  of  men  to  keep  them  in  proper  repair  and  operation.  Un- 
doubtedly the  sets  would  be  smalier  if  they  were  using  richer  gas, 
but  I  doubt  whether,  at  the  present  time,  the  best  gas  engine  set, 
working  under  its  best  conditions,  can  compete  with  the  best  steam 


DISCUSSION  871 

turbine  set,  working  under  its  best  conditions.  With  regard  to  the 
future,  the  chance  would  seem  to  favor  the  turbine  more  and  more, 
for  the  efficiency  of  the  turbine  is  improving  rapidly  and  continuously, 
whereas  that  of  the  gas  engine  is  not  so  marked.  The  author  speaks 
of  the  competition  between  the  gas  engine  and  the  steam  turbine, 
which  lately  has  become  very  keen  in  Germany  as  well  as  in  the 
United  States.  I  am  under  the  impression  that  the  competition  is 
becoming  less  keen  and  that  the  arguments  are  more  and  more  in 
favor  of  the  turbine.  Several  years  ago,  the  Mond  people  in  England 
were  producing  and  distributing  power  gas  on  a  large  scale,  but  I 
believe  their  installations  do  not  increase  much,  and  that  the  progress 
made  by  gas  plants  generally  during  the  last  few  years  has  not  been 
anything  like  so  marked  as  that  made  by  the  turbine,  except  that  gas 
plants  have  been  utilized  in  steel  mills  and  other  places  where  gas 
is  to  be  had  under  unusually  favorable  conditions. 

A  comparison  of  the  theoretical  costs  of  production  of  electric 
energy  by  a  large  gas-driven  plant  and  by  a  steam-driven  plant  of 
the  same  total  capacity,  assuming  both  of  them  to  be  situated  at  the 
coal  pit  and  burning  all  the  coal  brought  up  from  it,  would  be  very 
interesting.  I  would  like  to  ask  whether  such  costs  have  ever  been 
prepared  and  if  not,  whether  the  author  considers  that  they  would 
argue  in  favor  of  the  gas-driven  sets. 

F.  Z.  NEDUEN,  in  reply  to  a  question,  referred  to  the  Humphrey 
pump  recently  installed  in  Chingford  near  London.  The  problem  of 
using  the  Humphrey  pump  as  a  generator  of  electricity  has  been 
taken  up  by  the  Siemens- Schuckert  Works  of  Berlin.  They  are 
actively  engaged  in  tests  with  the  object  of  generating  electricity  by 
means  of  a  water  turbine  driven  by  water  raised  by  a  Humphrey 
pump.  The  water  after  passing  the  turbine  circulates  through  the 
pump  again.  So  far  nothing  has  been  published  as  to  the  economy 
of  the  system.  Such  a  plant  would  seem  to  be  the  proper  spare  for 
a  low  fall  water  turbine  during  periods  of  shortage  in  water.  Instead 
of  using  a  separate  spare  generator  set  driven  by  a  steam  or  internal- 
combustion  engine,  the  water  would  simply  have  to  be  pumped,  by  a 
Humphrey  pump,  from  the  tail-water  back  to  the  headwater  and 
flow  through  the  water  turbine  again,  thereby  saving  expense  for  a 
spare  generator  and  simplifying  service. 

THE  AUTHOR.  Referring  to  the  discussion  by  Mr.  Freyn,  while 
regulation  by  throttling  the  gas  only  will  produce  a  smoothly  running 
engine,  I  prefer  to  throttle  air  and  gas  simultaneously. 


872  THE  LARGE  GAS  ENGINE  IN  EUROPE 

In  reference  to  cylinders,  cracked  cylinders  which  have  been 
calked  have  lasted  a  good  many  years  and  very  many  of  them  are 
still  in  use.  It  does  not  weaken  or  damage  the  cylinder  if  cracks  are 
noticed  soon  and  calked.  The  crack  gives  some  relief  to  the  lamina 
which  is  exposed  to  the  highest  temperatures  and  strains. 

With  regard  to  the  objections  in  connection  with  the  surcharging 
of  the  machine  mentioned  in  the  paper,  I  do  not  want  to  imply  that 
the  strains  are  due  to  the  greater  mechanical  forces  acting.  There 
is  no  question  that  by  reducing  the  compression  pressure  it  is  possible 
to  work  with  the  same  maximum  explosion  pressure,  at  the  same  time 
having  from  20  to  25  per  cent  higher  mean  effective  pressure.  The 
strains  referred  to  are  not  caused  by  mechanical  forces  but  by  heating. 
In  this  matter  I  cannot  draw  on  my  own  experience,  but  I  have  heard 
that  the  temperatures  of  the  cylinders  are  increasing.  This  would 
mean  an  increase  of  strain  in  the  cylinder  walls  due  to  the  surcharging 
of  the  engines. 

In  reply  to  Mr.  Nediden,  I  have  no  special  information  on  the 
surface-combustion  boilers.  Generally  it  is  said  that  the  cylindrical 
surfaces  on  which  the  combustion  takes  place  are  filled  with  dust  in 
a  short  time  and  put  out  of  service.  This,  I  think,  is  not  a  serious 
inference,  since  it  should  be  possible  to  produce  combustion  cylinders 
at  such  a  cheap  price  that  it  will  be  practicable  to  "scrap"  them  when 
necessary. 

Professor  Fernald  asked  about  the  si2e  of  gas  engines.  When  we 
speak  of  large  gas  engines  it  means  engines  of  1000  h.p.  and  upwards. 
Double-acting  engines  of  less  than  about  35  in.  or  36  in.  diameter  of 
cylinder  are  not  built  at  all,  at  least  in  Germany.  The  limit  of  the 
size,  according  to  our  experience  there,  is  about  55-in.  bore,  by  6-ft. 
stroke.  Tandem  engines  of  this  sort  would  carry  a  load  of  3500  h.p., 
which  means  a  twin  unit  of  6000  or  7000  h.p.,  about  the  maximum 
limit.  This  limit  is  not  determined  by  shop  practice  or  by  designing, 
but  by  the  impossibility  of  shipping  by  rail  larger  sizes  of  frames, 
cylinders  and  tie  pieces. 

I  agree  with  Professor  Fernald  with  regard  to  the  production  of 
electric  power  at  the  mines.  Power  can  be  produced  at  the  mines 
for  generating  electricity  and  the  current  transmitted  at  100,000  or 
150,000  volts,  which  voltages  T  understand  are  being  used  in  this 
country.  Whether  these  big  central  stations  will  use  gas  engines  or 
steam  turbines  is  very  hard  to  say;  the  question  will  probably  be 
decided  to  a  large  extent  by  financial  considerations. 


CLOSURE  873 

While  big  units  with  piston  engines  are  limited  to  6000  or  7000 
h.p.,  no  limitations  are  given  for  the  gas  turbine,  and  this  problem 
certainly  represents  the  next  advance  to  be  made  by  the  mechanical 
engineer. 

In  reference  to  waste  heat  boilers  (in  reply  to  a  question),  I  can- 
not give  the  data  on  the  necessary  heating  surface  of  these  boilers. 
But  it  is  not  advisable  to  use  too  much  of  heating  surface,  for  it  is 
necessary  to  discharge  waste  gases  with  temperatures  of  200  or  220 
deg.,  in  order  to  prevent 'the  condensation  of  the  steam  vapor  in  the 
exhaust  gases  and  corrosion  of  the  tubes,  as  sulphur  is  found,  in  any 
of  the  industrial  gases. 


]So   1421 

EXTINGUISHING  OF  FIRES  IN  OILS  AND 
VOLATILE  LIQUIDS 

EDW.  A.  BARBiER,1  BOSTON,  MASS. 
Non-Member 

The  extinguishing  of  fires  in  oils  and  in  most  of  the  volatile 
liquids  has  always  been  a  difficult  problem  and  where  fires  of  this  kind 
occur  the  results  are  frequently  very  disastrous.  Our  most  common  ex- 
tinguishing agent,  water,  works  rather  unsatisfactorily  upon  the  ma- 
jority of  such  fires,  but  it  is  still  the  only  one  available  where  heroic 
measures  are  required.  Comparatively  recently,  however,  there  have 
been  two  or  three  other  materials  introduced  for  use  as  extinguishers 
which  have  shown  some  promise  for  dealing  with  these  fires,  and  it 
is  the  purpose  of  this  paper  to  discuss  these  materials  and  the  con- 
ditions under  which  they  prove  the  most  efficient. 

2  Not  all  fires  in  volatile  liquids  are  difficult  to  handle  with 
water.     When  the  liquid  is  miscible  with  water  this  extinguishing 
agent  can  be  successfully  used.    Examples  of  this  kind  are  denatured 
alcohol,  wood  alcohol,  grain  alcohol,  acetone,  etc.    Where  the  liquid 
is  not  miscible  with  water  little  or  no  effect  is  produced  except  to  wash 
the  burning  liquid  out  of  the  building  where  it  may  be  completely 
consumed  or,  if  the  quantity  of  oil  is  small,  possibly  to  extinguish  the 
fire  by  the  brute  cooling  effect  of  a  large  quantity  of  water  sprayed 
upon  the  fire.     Soda  and  acid  extinguishers  are  somewhat  more  effec- 
tive than  pure  water,  but  even  they  fail  under  most  conditions.    The 
various  grenades  containing  salt  solutions  which  were  formerly  ex- 
tensively exploited  are  of  course  practically  worthless. 

3  The  only  principles  that  can  be  made  use  of  in  extinguishing 
fires  in  volatile  oils  are,   (a)  to  form  a  blanket  either  of  gas  or  of 
solid  material  over  the  burning  liquid  which  will  exclude  the  oxygen 
of  the  air,  or,  (6)  to  dilute  the  burning  liquid  with  a  non-inflammable 
extinguishing  agent  which  is  miscible  with  it. 

1  Inspection  Department,  Associated  Factory  Mutual  Fire  Insurance  Com- 
panies, 31  Milk  Street. 


Presented  at  the  Annual  Meeting   1913,   of  THE   AMERICAN   SOCIETY  OF 
MECHANICAL  ENGINEERS. 

889 


890  EXTINGUISHING    OF    FIRES 

SAWDUST    AND   BICAKBONATE    OF    SODA 

4  To    the   blanketing  type   of   extinguishers   belongs   sawdust. 
Paradoxical  as  it  may  seem,  ordinary  sawdust  is  an  excellent  ex- 
tinguishing agent  for  certain  volatile  liquids,  especially  those  of  a 
viscous  nature.     A  considerable  number  of  experiments  were  con- 
ducted in  the  fall  of  1912  by  the  inspection  department  of  the 
Associated  Factory  Mutual  Fire  Insurance  Companies,  in  the  ex- 
tinguishing of  fires  in  lacquer  and  gasolene  in  tanks  with  sawdust, 
and  the  results  were  surprisingly  satisfactory. 

5  The  liquids  were  placed  in  three  tanks  30  in.  long,  12  in.  wide 
and  16  in.  deep;  48  in.  long,  14  in.  wide  and  16  in.  deep;  and  60  in. 
long,  30  in.  wide  and  16  in.  deep.    The  sawdust  was  applied  with  a 
long-handled,  light  but  substantially  built  snow  shovel  having  a  blade 
of  considerable  area.    In  every  case  the  fires  were  extinguished  readily, 
especially  in  the  two  smaller  tanks  which  were  about  as  large  as  any 
ordinarily  employed  for  lacquer  in  manufacturing  establishments. 

6  The  efficiency  of  the  sawdust  is  undoubtedly  due  to  its  blanket- 
ing action  in  floating  for  a  time  upon  the  surface  of  the  liquid  and 
excluding  the  oxygen  of  the  air.    Its  efficiency  is  greater  on  viscous 
liquids  than  on  thin  liquids,  since  it  floats  more  readily  on  the  former 
than  on  the  latter.    The  sawdust  itself  is  not  easily  ignited  and  when 
it  does  become  ignited  it  burns  without  flame.    The  burning  embers 
have  not  a  sufficiently  high  temperature  to  reignite  the  liquid. 

7  The  character  of  the  sawdust,  whether  from  soft  wood  or  hard 
wood,  appears  to  be  of  little  or  no  importance,  and  the  amount  of 
moisture  contained  in  it  is  apparently  not  a  factor,  so  that  the  drying 
out  of  sawdust  when  kept  in  manufacturing  establishments  for  a  time 
would  not  affect  the  efficiency. 

8  It  was  found  that  the  admixture  of  sodium  bicarbonate  greatly 
increased  the  efficiency  of  the  sawdust  as  shown  both  by  the  shortened 
time  and  the  decreased  amount  of  material  necessary  to  extinguish 
the  fires.    A  further  advantage  of  the  addition  of  bicarbonate  of  soda 
is  that  it  decreases  the  possible  danger  resulting  from  the  presence  of 
sawdust  in  manufacturing  plants  since  it  would  be  difficult,  if  not 
impossible,  to  ignite  the  mixture  by  a  carelessly  thrown  match  or  any 
other  ready  source  of  ignition. 

9  Although  the  efficiency  of  the  sawdust  is  greatest  on  viscous 
liquids  such  as  lacquers,  heavy  oils,  japan,  waxes,  etc.,  in  the  tests 
referred  to,   fires  were   extinguished  in  gasolene   contained  in   the 


EDW.    A.    BAEHIEB  891 

smallest  tank  and  also  when  spread  upon  the  ground.  In  larger  tanks 
the  sawdust  or  bicarbonate  mixture  does  not  work  so  well  since  the 
sawdust  sinks  before  the  whole  surface  can  be  covered,  whereupon  the 
exposed  liquid  reignites. 

CARBON   TETRACHLORIDE 

10  In  recent  years  carbon  tetrachloride  has  received  considerable 
attention  as  a  fire-extinguishing  agent.     This  is  due  largely  to  the 
activity  of  certain  manufacturers  of  fire  extinguishers  which  use 
liquids,  the  basis  of  which  is  carbon  tetrachloride. 

11  This  substance  is  a  water  white  liquid  and  possesses  when 
pure  a  rather  agreeable  odor  somewhat  similar  to  chloroform.     A 
considerable  proportion  of  the  commercial  article  upon  the  market, 
however,  contains  sulphur  impurities  which  impart  a  disagreeable 
odor  to  the  liquid.    The  substance  is  quite  heavy,  its  specific  gravity 
being  1.632  at  32  deg.  fahr.     It  is  non-inflammable,  non-explosive, 
and  is  readily  miscible  with  oils,  waxes,  japan,  etc.    When  mixed  with 
inflammable   liquids   it  renders   them   non-inflammable   provided   a 
sufficient  quantity  is  added.    Its  vapor  is  heavy,  the  specific  gravity 
being  about  five  and  one-half  times  that  of  air,  consequently  it  settles 
very  rapidly.     As  an  extinguishing  agent  it  operates  by  both  the 
principles  mentioned  in  Par.  3,  namely,  it  dilutes  the  inflammable 
liquid  rendering  it  non-inflammable,  or  at  least  less  inflammable,  and 
it  forms  a  blanket  of  gas  or  vapor  over  the  burning  liquid  which  ex- 
cludes the  oxygen  of  the  air. 

12  Although  this  paper  is  confined  to  a  discussion  of  extinguish- 
ing fires  in  oils  and  volatile  liquids,  it  may  not  be  out  of  place  to 
mention  that  the  claims  made  by  certain  manufacturers  producing 
these  extinguishers  which  use  liquids,  the  basis  of  which  is  carbon 
tetrachloride,  are  grossly  exaggerated.     These  preparations,  none  of 
which  is  more  efficient  than  carbon  tetrachloride,  are  not  the  equivalent 
of  the  ordinary  water  extinguishers  for  general  use  on  such  materials 
as  cotton,  wood,  paper,  oily  waste,  etc. 

13  On  volatile  liquids,  oils,  etc.,  carbon  tetrachloride  has,  how- 
ever, shown  very  satisfactory  results  under  some  conditions,  but  the 
readiness  with  which  a  fire  can  be  extinguished  with  it  depends  to  a 
considerable  extent  upon  the  skill  of  the  operator  and  the  nature  of 
the  fire.     In  tank  fires  the  length  of  time  that  the  liquid  has  been 
burning  is  an  important  factor,  and  in  such  cases  where  the  sides  of 
the  tank  become  heated  the  only  way  in  which  the  fire  can  be  ex- 


892  EXTINGUISHING    OF    FIRES 

tinguished  is  to  squirt  the  liquid  forcibly  at  the  sides.  If  the  carbon 
tetrachloride  is  squirted  directly  into  the  liquid  it  is  much  more 
difficult,  if  not  impossible,  to  extinguish  the  fire. 

14  The  height  of  the  liquid  in  the  tank  is  also  a  very  important 
factor.    Where  the  liquid  is  low  the  sides  form  a  pocket  which  retains 
the  vapor  and  aids  considerably  in  smothering  the  blaze.    When  the 
tank  is  nearly  full,  however,  this  condition  does  not  exist,  and  it  is 
then  very  difficult,  if  not  impossible,  to  extinguish  a  fire  in  a  highly 
volatile  liquid,  such  as  gasolene;  only  the  most  skilled  operators  are 
successful  in  these  cases.     The  size  of  the  tank  or  the  extent  of  the 
fire  if  upon  the  floor  is,  as  would  be  expected,  of  considerable  import- 
ance.    In  tanks  larger  than  about  28  in.  by  12  in.  more  than  one 
extinguisher  and  operator  working  at  a  time  are  necessary  to  ex- 
tinguish a  fire  in  such  materials  as  gasolene.     In  one  test  where  a 
tank  60  in.  by  30  in.  was  used  no  less  than  seven  operators  were 
necessary,  and  even  then  it  was  only  with  the  greatest  difficulty  that 
the  fire  was  put  out. 

15  All  of  the  above  remarks  apply  to  carbon  tetrachloride  in  the 
ordinary  one-quart  extinguisher  as  generally  sold.     It  is  probable 
that  a  large  extinguisher  which  could  throw  a  large  stream  would 
prove  more  efficient,  but  on  account  of  the  great  weight  of  carbon 
tetrachloride  such  an  extinguisher  would  have  to  be  specially  designed 
to  make  it  readily  portable  by  mounting  on  a  truck  or  some  similar 
means.     Expelling  the  liquid  by  means  of  a  hand-pumping  arrange- 
ment would  probably  be  unsatisfactory,  and  it  would  therefore  be 
necessary  to  force  it  out  in  some  other  way. 

16  A   few   systems   have   recently  been   installed   in   which    an 
elevated  tank   containing   carbon   tetrachloride  was   connected   with 
automatic  sprinklers  or  perforated  pipes  located  in  hazardous  rooms 
where  volatile  and  inflammable  liquids  are  in  use.    So  far  as  is  known 
none  of  these  systems  have  as  yet  been  called  upon  to  extinguish  a 
fire,  but  there  appears  to  be  no  reason  why  such  a  system  should  not 
provide  excellent  protection  in  special  cases.    In  such  systems  it  would 
be   necessary  to   consider  the   safety  of   the   workmen   and  furnish 
ready  means  of  escape,  since  carbon  tetrachloride  is  an  anesthetic  and 
where  thoroughly   sprayed  through  the  air   as  from  an   automatic 
sprinkler  it  would  probably  produce  rapid  results. 

17  The  nature  and  effect  of  the  fumes  given  off  when  carbon 
tetrachloride  is  thrown  upon  a  fire  is  a  subject  which  has  received 
a  great  deal  of  discussion.    When  the  liquid  comes  in  contact  with  a 


EDW.    A.    BARRIER  893 

fire  the  vapor  is  partly  decomposed  resulting  in  the  evolution  of  a 
considerable  quantity  of  black  smoke  which  is  undoubtedly  finely 
divided  carbon.  Pungent  gases  are  also  produced  which  appear  to  be 
mostly  hydrochloric  acid  with  possibly  a  small  amount  of  chlorine. 
Since  carbon  tetrachloride  contains  no  hydrogen  from  which  hydro- 
chloric acid  could  be  formed  this  substance  must  be  produced  by  the 
action  of  chlorine  on  the  gases  arising  from  the  burning  material  or 
upon  the  moisture  of  the  air. 

18  The  fumes  of  carbon  tetrachloride  although  of  a  very  pungent 
nature  do  not  produce  any  permanent  injury  under  ordinary  con- 
ditions where  the  operator  can  make  his  escape  after  he  has  inhaled 
all  that  he  can  stand,  but  they  are  a  distinct  handicap  in  fighting  a 
fire  and  are  one  of  the  objectionable  features  to  carbon  tetrachloride 
as  a  general  fire  extinguishing  agent.     In  large  rooms  or  where  a 
small  quantity  of  carbon  tetrachloride  is  sufficient  to  extinguish  a  fire 
the  gases  are  of  course  less  objectionable. 

FROTHY   MIXTURES 

19  Another  method  of  extinguishing  fires  in  oils  and  volatile 
liquids  which  has  recently  been  proposed  and  experimented  with  is 
that  of  using  frothy  mixtures.    The  idea  seems  like  a  very  promising 
one  and  the  tests  which. have  been  thus  far  reported  indicate  very 
satisfactory  results.    The  idea  was  originated  and  has  been  developed 
in  Germany.    So  far  as  is  known  no  experiments  have  been  conducted 
in  this  country. 

20  The  process  consists  essentially  in  causing  two  liquids  to  mix 
in  a  tank  where  foam  is  produced.     The  tank  is  made  airtight  and 
sufficiently  strong  to  permit  of  the  foam  being  forced  out  by  carbon 
dioxide  under  pressure,  and  the  foam  is  conveyed  to  the  fire  by  means 
of  a  line  of  hose.  The  exact  nature  of  the  liquids  has  not  been  disclosed, 
but  one  of  them  probably  consists  of  a  sodium  carbonate  solution  con- 
taining froth-forming  ingredients  such  as  glue  or  casein  and  the 
other  an  alum  solution.    The  two  on  coming  together  generate  carbon 
dioxide  which  produces  froth.    This  froth  is  reported  to  be  quite  stiff 
and  to  shrink  in  volume  but  a  comparatively  small  amount  even  after 
a  period  of  half  an  hour. 

21  A  number  of  tests  were  conducted  in  the  winter  of  1912  in 
Germany ;  some  of  them  on  a  considerable  scale.    In  one  case  as  much 
as  5  tons  of  crude  naphtha  in  a  tank  was  involved,  and  in  another  an 
area  of  1300  sq.  ft.  of  burning  tar  was  used.    In  all  cases  the  results 


894  EXTINGUISHING   OF   FIRES 

were  reported  satisfactory,  the  fires  being  extinguished  in  a  short 
time. 

22  The  frothy  mixture  undoubtedly  owes  its  efficiency  to  its 
blanketing  action  in  settling  upon  the  surface  of  the  burning  liquid, 
thus  excluding  the  oxygen  of  the  air,  and  to  the  fact  that  the  bubbles 
of  liquid  contain  carbon  dioxide  which  upon  bursting  produce  an 
atmosphere  in  which  combustion  cannot  take  place. 

23  According  to  the  latest  reports  the  matter  is  still  in  an  ex- 
perimental stage,  various  details  regarding  the  form  of  apparatus, 
most  efficient  pressure,  and  design  of  nozzles  being  under  considera- 
tion; but  from  what  has  already  been  done  it  would  appear  that  the 
idea  is  a  very  promising  one,  and  that  this  method  of  extinguishing 
fires  in  oils  and  volatile  liquids  will  prove  to  be  by  far  the  most 
efficient  of  any  that  has  as  yet  been  suggested. 

DISCUSSION 

A.  E.  CLUETT.  As  I  understand  it,  the  tank  was  an  open  one,  of 
rectangular  section,  which  does  not  represent  the  conditions  in  which 
these  liquids  are  ordinarily  found.  They  are  generally  in  a  closed 
tank,  with  a  bung-hole  of  some  description,  and  I  would  like  to  ask 
whether  any  experiments  have  been  made  on  such  receptacles,  and 
also  whether  experiments  have  been  conducted  where  the  fluid  has 
been  spread  out  as  it  would  be  if  it  were  spilled  over  a  floor. 

J.  STEWART  THOMSON  (written).  The  author  of  the  paper  oc- 
cupies a  position  in  connection  with  an  organization  insuring 
sprinklered  risks,  which  makes  no  recognition  whatever  of  devices  for 
the  extinguishing  of  fires  other  than  by  sprinklers.  His  remarks  are 
the  result  of  some  tests  made  by  him  in  connection  with  devices  other 
than  sprinklers. 

It  is  generally  known  that  fires  in  volatile  liquids  which  are  not 
miscible  with  water  cannot  be  extinguished  by  the  application  of 
water.  The  reason  is  perfectly  apparent;  and  that  the  way  to  ex- 
tinguish a  fire  in  volatile  liquids  of  this  type  is  to  blanket  the  flame 
or  to  dilute  the  liquid  with  a  non-inflammable  extinguishing  agent, 
thus  cooling  the  liquid  to  the  point  where  it  will  not  burn. 

The  use  of  sawdust  in  connection  with  fires  of  this  character  is 
not  new.  Almost  every  one  has  at  one  time  or  another  used  a  blanket, 
towel  or  something  similar  for  the  purpose  of  smothering  a  fire.  We 
all  know  that  sawdust  will  float  for  a  time  at  least  on  the  surface  of 


DISCUSSION  BY  J.  S.  THOMSON  895 

the  liquid,  and  that  if  the  sawdust  is  put  on  in  quantity  it  acts  as  a 
blanket.  As  a  practical  fire  extinguishing  agent,  however,  the  use  of 
sawdust  is  not  practical.  In  a  large  tank  of  burning  liquid  of  the 
type  described,  before  the  surface  can  be  covered  with  the  blanket, 
much  of  the  sawdust  will  sink  below  the  surface  whereupon  the  ex- 
posed liquid  reignites. 

As  to  the  use  of  carbon  tetrachloride  as  a  means  of  extinguishing 
fires  in  oils  and  volatile  liquids,  there  are  some  40  different  devices 
on  the  market  employing  this  substance.  Carbon  tetrachloride  has 
been  found  to  be  remarkably  efficient;  a  quart  of  this  liquid  contains 
approximately  149  cu.  ft.  of  fire  extinguishing  gas.  As  Mr.  Barrier 
states,  carbon  tetrachloride  contains  sulphur  impurities.  Its  use  in 
a  metal  container  results  after  a  period  of  time  in  the  corrosion  of 
the  metal.  Extinguishers  generally  employing  this  chemical  have  not 
been  found  to  have  long  life  and  corrosion  of  the  metal  results  in  the 
clogging  of  the  working  parts  of  the  extinguisher.  These  ex- 
tinguishers have  the  additional  drawback  of  operating  by  air  pressure ; 
it  is  a  well-known  fact  that  air  cannot  be  contained  over  any  very  long 
period  in  a  metal  container  with  valves,  outlets,  petcocks,  etc. 

The  manufacturers  of  the  Pyrene  extinguisher  discovered  the 
efficiency  of  carbon  tetrachloride  as  an  extinguishing  agent  many  years 
ago,  but  also  that  this  article  is  corrosive  in  its  action  upon  metals. 
It  was  necessary  to  alter  the  nature  of  carbon  tetrachloride  in  respect 
to  this  before  it  could  be  used  successfully  in  a  fire  extinguisher.  They 
also  discovered  that  it  was  possible  to  increase  the  efficiency  of  the 
liquid. 

While  the  claim  is  not  made  by  the  author,  the  inference  would 
be  from  his  paper  that  carbon  tetrachloride  is  virtually  the  same  as 
the  extinguishing  agent  employed  by  the  Pyrene  Manufacturing  Com- 
pany, in  his  reference  to  "the  activity  of  certain  manufacturers  of  fire 
extinguishers  which  use  liquids,  the  basis  of  which  is  carbon  tetra- 
chloride." He  is  probably  not  informed  that  one  quart  of  Pyrene 
will  generate  approximately  33  V3  per  cent  more  fire  extinguishing 
gases  than  carbon  tetrachloride ;  therefore  it  will  cover  more  fire.  The 
one-quart  pump-type  Pyrene  extinguisher  has  been  approved  by  the 
Chicago  Laboratories,  Inc.,  and  is  in  universal  use  throughout  the 
country;  is  uniformly  recognized  in  every  state  for  fires  of  the  type 
described  by  him,  and  that  its  record  of  efficiency  in  respect  to  these 
fires  is  remarkable. 

In  his  statement  in  Par.  12,  Mr.  Barrier  ignores  the  amount  of 


896  EXTINGUISHING   OF   FIEES 

extinguishing  gas  referred  to  above.  Extinguishers  of  this  type  are 
more  efficient  in  cotton  fires  and  fires  in  oily  waste,  etc.,  than  those 
employing  solutions  of  water. 

In  the  test  where  a  60-in.  by  30-in.  tank  was  used,  where  it  required 
a  number  of  operators  to  extinguish  a  fire  of  burning  gasolene,  he 
should  certainly  have  had  no  difficulty  in  extinguishing  a  fire  in  a 
tank  of  these  dimensions  if  the  extinguisher  had  been  properly 
handled. 

Mr.  Barrier  concludes  that  the  use  of  soapsuds,  described  as 
"frothy"  mixtures  in  extinguishing  fires  in  oils  and  volatile  liquids, 
will  prove  by  far  the  most  efficient  of  any  that  has  yet  been  suggested, 
but  statistics  will  not  bear  out  the  conclusion.  This  method  has  been 
employed  to  some  extent  on  the  Continent  and  in  England  for  some 
time,  and  experiments  have  also  been  conducted  in  this  country  which 
are  the  subject  of  extensive  reports.  The  progress  of  extinguishers 
working  on  this  principle,  however,  has  been  inconsiderable  as  com- 
pared with  the  progress  of  other  extinguishers,  and  notably,  as  com- 
pared with  the  progress  made  by  the  Pyrene  extinguishers. 

HENRY  W.  APPLETON.  I  would  ask  Mr.  Barrier  what  he  con- 
siders the  proper  proportion  of  soda  carbonate  in  the  sawdust,  and 
what  effect  is  produced  on  the  sawdust  to  make  it  non-inflammable; 
that  is,  not  only  the  percentage  to  be  used  to  make  it  efficient  in 
putting  out  the  fire,  but  also  the  percentage  to  be  used  in  rendering 
the  sawdust  itself  non-inflammable. 

LEWIS  H.  KUNHARDT.  Mr.  Thomson's  statement,  that  the  au- 
thor occupies  a  position  in  connection  with  an  organization  insuring 
sprinklered  risks,  which  makes  no  recognition  whatever  of  devices  for 
the  extinguishing  of  fires  other  than  by  sprinklers,  needs  modification. 
It  is  absolutely  at  variance  with  the  fact.  Not  only  do  the  Mutual 
Companies  give  credit  for  many,  and  practically  all  devices  which  are 
used  in  extinguishing  fires,  but  all  the  various  sprinkler  risk  associa- 
tions, underwriters  and  others  throughout  the  country,  are  con- 
tinuously studying  all  these  other  devices.  Sprinklers  are  only  a  part 
of  the  fire  protection  of  'a  piece  of  property.  If  other  devices  fail,  the 
sprinklers  come  in  and  assist,  and  if  the  sprinklers  should  fail,  there 
are  the  fire  pumps,  hose,  etc.  All  the  various  fire  protection  engineers 
in  the  country  are  studying  these  problems  and  details  thoroughly, 
and  they  do  not  give  recognition  only  to  the  automatic  sprinkler, 
although  they  recognize  the  value  of  it,  and  know  it  to  be  one  of  the 
best  fire  fighting  agencies  of  today. 


DISCUSSION  897 

ALBERT  BLAUVELT.  As  Mr.  Kunhardt  comments,  this  paper  by 
Mr.  Barrier  covers  a  subject  in  itself  and  one  which  is  not  tied  to 
automatic  sprinkler  practice.  The  use  of  hand  apparatus  is  universal 
in  all  branches  of  fire  protection  practice  in  preference  to  waiting  for 
sprinklers  to  fuse,  or  to  waiting  for  hose,  and  the  greatest  success  of 
the  professional  fire  department  so  far  as  the  majority,  or  some  70  to 
80  per  cent  of  the  fires  numerically  are  concerned,  is  accomplished 
with  hand  appliances,  or  usually  the  carbonic-acid  gas  extinguishers 
carried  on  the  man's  back  as  he  jumps  off  the  hose  cart. 

The  general  scope  of  hand  apparatus  is  fairly  broad,  depending  on 
the  combustible  to  be  dealt  with  and  whether  ceiling  as  well  as  floor 
fires  are  likely  to  need  extinguishment.  Tinder  its  title,  the  teaching 
of  Mr.  Barrier's  paper  would  seem  to  be  that  this  subject  of  handling 
oil  or  volatile  or  chemical  fires  is  not  a  mystery.  Doubtless,  as  sug- 
gested by  a  preceding  speaker,  the  paper  can  be  bettered  by  giving 
more  detail  as  to  the  best  proportions  for  the  several  useful  mixtures, 
but  the  main  thing  is  that  those  wTho  will  can  make  up  effective  ex- 
tinguishing compounds  for  volatile  liquid  or  oil  fires,  not  perhaps  of 
the  exact  alchemic  virtue  of  the  trade  compounds  but  probably  obtain 
twenty  times  the  quantity  at  like  cost. 

GORIIAM  DANA.1  This  paper  seems  to  cover  the  field  remarkably 
well,  but  there  is  one  point  I  would  like  to  bring  up  in  connection 
with  carbon  tetrachloride,  and  that  is  the  effect  which  the  gas  might 
have  on  metals  in  the  vicinity.  At  a  fire  some  time  ago  in  a  garage, 
an  attempt  was  made  to  extinguish  a  pail  of  burning  gasolene  with 
these  extinguishers.  They  not  only  failed  to  extinguish  the  fire,  but 
the  gases  given  off  were  of  such  a  corrosive  nature,  probably  hydro- 
chloric acid,  that  the  damage  done  to  the  metal  work  on  the  automo- 
biles and  in  the  garage,  was  more  than  the  direct  loss  from  the  fire 
itself. 

F.  E.  CARDULLO.  The  claim  has  been  made  in  this  discussion  that 
one  quart  of  carbon  tetrachloride  at  atmospheric  pressure  liberates  a 
volume  of  149  cu.  ft.  of  inert  gas.  A  hasty  calculation  based  upon 
my  memory  of  the  density  of  air  gives  for  the  volume  of  carbon  tetra- 
chloride vapor  liberated  from  one  quart  of  liquid  a  value  of  approxi- 
mately 8  cu.  ft.  From  the  data  given  by  Peabody  in  his  steam  tables, 
the  volume  of  saturated  vapor  liberated  at  atmospheric  pressure  from 

1  Manager,   The  Underwriters'   Bureau  of  New  England,   141   Milk  Street, 
Boston,  Mass. 


EXTINGUISHING    OF   FIRES 

one  quart  of  carbon  tetraehloride  is  9.97  cu.  ft.  From  data  based 
upon  the  theoretical  vapor  density  of  carbon  tetraehloride  the  volume 
of  the  vapor  generated  from  a  quart  of  the  liquid  at  a  temperature 
of  135  deg.  fahr.,  and  a  pressure  of  one  atmosphere,  is  9.8  cu.  ft. 

It  may  be  added  that  if  the  gas  given  off  occupied  a  volume  of 
149  cu.  ft.,  it  would  be  so  light  as  to  rise  in  the  air  and  would  have 
no  smothering  effect  upon  the  fire.  I  would  suggest  that,  in  discus- 
sion, our  members  ought  to  be  exceedingly  careful  of  their  facts,  and 
not  to  quote  any  figures,  or  to  make  any  statements,  of  the  truth  of 
which  they  are  not  absolutely  certain. 

THE  AUTHOR.  Eeplying  to  the  question  of  Mr.  Cluett,  all  the 
experiments  with  these  materials  were  tried  in  open  containers,  since 
that  is  the  way  lacquer  is  ordinarily  used  in  most  metal- working 
plants.  The  metal  parts  are  generally  dipped  into  the  lacquer.  No 
tests  were  tried  on  closed  tanks,  and  it  would  be  difficult  to  use  saw- 
dust and  bicarbonate  of  soda  in  such  a  tank.  It  might  be  possible  to 
introduce  carbon  tetraehloride  under  such  conditions.  One  of  the 
tests  did  include  a  fire  in  lacquer  spread  over  a  wooden  platform  which 
served  as  a  floor,  and  the  sawdust  appeared  to  work  very  satisfactorily 
in  this  case. 

"With  reference  to  the  comments  of  Mr.  Thomson,  I  would  say 
that  I  recognize  that  sawdust  as  an  extinguishing  agent  is  not  new, 
but  it  is  not  well  known,  and  this  fact  is  shown  by  the  experience  we 
have  had  where  this  material  has  been  recommended  to  manufacturing 
establishments  throughout  the  country.  At  first  their  attitude  was 
one  of  great  surprise  but  after  they  had  conducted  a  few  tests  of  their 
own,  they  were  very  well  pleased  with  the  results.  This  shows  that 
even  though  the  idea  may  not  have  been  new,  it  was  at  least  not  at  all 
well  known  and  the  feature  of  mixing  bicarbonate  of  soda  with  the 
sawdust  is  a  new  and  valuable  one. 

It  was  not  my  intention  to  mention  any  particular  commercial 
device,  but  in  view  of  the  fact  that  the  Pyrene  extinguisher  has  been 
brought  into  the  discussion,  I  will  say  that  with  reference  to  the  matter 
of  the  corrosive  action  of  carbon  tetraehloride,  tests  were  conducted 
in  a  Pyrene  extinguisher  with  an  ordinary  garden  variety  of  carbon 
tetraehloride,  the  usual  commercial  article,  in  which  the  liquid  re- 
mained in  the  extinguisher  for  over  a  year,  but  as  far  as  could  be 
seen  after  using  a  can  opener  there  was  absolutely  no  indication  of 
corrosion.  In  certain  cases  where  moisture  or  hydrochloric  acid  are 


CLOSUKE  899 

present,  carbon  tetrachloride  does  cause  some  corrosion,  but  the  indi- 
cations are  that  if  a  reasonably  pure  grade  of  the  material  is  ob- 
tained, there  is  no  serious  trouble  from  this  source. 

As  to  the  comparative  efficiency  of  Pyrene  and  carbon  tetra- 
chloride, a  large  number  of  tests  were  made  to  compare  the  two 
liquids  when  both  were  used  under  the  same  conditions.  As  far  as  a 
number  of  unprejudiced  observers  could  determine,  there  was  no 
difference  in  the  efficiency  of  the  two.  It  is  true  that  Pyrene  contains 
a  few  other  substances  besides  carbon  tetrachloride,  among  which  is 
a  small  amount  of  gum,  which  by  the  way  is  combustible,  and  a  small 
amount  of  nitro  benzol  which  is  also  combustible;  both  of  these  are 
detrimental  rather  than  advantageous  as  far  as  extinguishing  a  fire  is 
concerned. 

With  reference  to  the  proportions  of  bicarbonate  of  soda  and  saw- 
dust, the  ingredients  are  mixed  in  the  proportion  of  about  8  Ib.  of 
bicarbonate  of  soda  to  a  bushel  of  sawdust.  This  proportion  does  not 
render  the  sawdust  non-combustible  but  it  does  retard  its  ignition. 
It  works  in  the  following  way:  If  a  spark  or  any  other  source  of 
ignition  conies  in  contact  with  the  mixture  in  the  vicinity  of  where 
the  bicarbonate  of  soda  is  located,  the  latter  becomes  heated  and  be- 
gins to  give  off  carbon  dioxide.  This  tends  to  make  the  atmosphere 
in  that  vicinity  a  non-supporter  of  combustion  and  serves  to  ex- 
tinguish or  retard  the  fire. 

In  reply  to  the  question  by  Professor  Woolson  as  to  whether  there 
is  any  tendency  toward  caking  after  the  sawdust  and  the  bicarbonate 
of  soda  have  been  standing  for  any  length  of  time,  I  may  say  that 
this  feature  has  been  pretty  thoroughly  tested  under  the  worst  possible 
conditions  and  after  a  period  of  six  or  eight  months  hardly  any  indi- 
cation of  caking  could  be  detected. 


No.  1422 

A  SYSTEM  FOR  THE  CONTROL  OF  AUTO- 
MATIC SPRINKLER  VALVES 

BY  FRED  J.  MILLER,  NEW  YORK 
Member  of  the  Society 

The  fires  in  the  Triangle  Shirtwaist  Factory  and  in  the  Bingham 
ton  Clothing  Company's  building,  have  served  strongly  to  emphasize 
the  fact  that  public  sentiment  is  more  and  more  placing  full  responsi- 
bility upon  the  owners  of  industrial  establishments  for  the  thorough 
protection  of  employees  from  death  by  fire.  This  responsibility  is 
being  reflected  in  legislation  requiring  the  provision  of  suitable  means 
of 'egress  from  buildings,  fire  drills,  fire  walls,  automatic  sprinklers, 
enforcement  of  rules  against  smoking,  etc. 

2  The  outside  fire  escape,  constructed  in  the  ordinary  manner,  was 
proved  in  both  the  fires  mentioned  above  and  in  numerous  other  fires 
as  well  to  be  almost,  if  not  absolutely  worthless.    It  is  extremely  diffi- 
cult for  a  large  number  of  employees,  especially  where  many  of  them 
are  women,  to  descend  the  ordinary  fire  escape,  even  when  there  is  no 
panic  and  no  reason  for  special  haste.     At  the  time  of  a  fire  it  is 
practically  useless. 

3  Fire  drills  are  probably  justifiable  and  have  in  many  cases  saved 
lives.    If  properly  maintained  they  are  expensive,  however,  and  in  both 
the  fires  referred  to  above  they  proved  worthless. 

4  Some  of  the  other  things  mentioned,  particularly  suitable  fire 
walls,  are  very  good,  but  experience  seems  to  have  proved  abundantly 
that  the  best  of  them  all  is  the  automatic  sprinkler.     In  theory,  at 
least,  it  is  supposed  to  be  always  ready  for  instant  use,  and  it  puts 
water  where  and  when  it  is  needed  at  the  very  beginning  of  a  fire, 
before  it  has  had  time  to  assume  threatening  proportions,  and  usually 
before  there  is  enough  smoke  to  alarm  the  occupants  of  the  building 
seriousty  or  start  a  panic. 

5  It  has  other  important  uses,  such  as  the  formation  of  an  effective 
water  curtain  capable  of  arresting  the  progress  of  a  fire  which  has 

Presented   at   the   Annual   Meeting   1913,    of   THE   AMERICAN   SOCIETY   OF 
MECHANICAL  ENGINEERS. 

901 


902  CONTROL  OF  AUTOMATIC  SPRINKLER  VALVES 

assumed  the  character  of  a  conflagration,  and  Mr.  Albert  Blauvelt 
and  Prof.  Ira  II .  Woolson  in  their  papers  read  at  the  Baltimore  meet- 
ing of  the  Society1  present  much  impressive  evidence  of  the  value  of 
sprinklers  when  maintained  in  such  working  order  as  to  be  available 
when  needed. 

6  The  National  Fire  Protection  Association,  through  its  committee 
-  on  safety  to  life,  investigated  the  Binghamton  Clothing  Company's 

fire  and  in  their  report,  commenting  upon  the  various  conditions  in 
the  building  and  particularly  upon  the  entire  absence  of  practically 
every  efficient  safeguard,  say: 

Long  experience  and  continually  repeated  demonstration  prove  that  the  auto- 
matic sprinkler,  where  properly  installed  and  in  operating  condition,  is  always 
ready,  operates  quickly,  and  either  extinguishes  fire  or  holds  it  in  check,  and  is 
the  most  reliable  means  of  safeguarding  lives  in  the  majority  of  existing 
manufacturing  buildings.  Enclosing  stairs,  building  fire  towers,  properly  con- 
structing fire  escapes,  etc.,  are  all  means  intended  to  permit  of  escape  after 
the  fire  gets  under  way.  The  automatic  sprinkler  almost  invariably  prevents 
the  fire  from  assuming  serious  proportions. 

7  This   statement   by   an   association   which   has   made    a   very 
thorough  study  of  the  whole  problem  of  the  lessening  of  fire  loss  and 
the  protection  of  lives  from  destruction  by  fire,  is  borne  out  by  the 
experience  of  the  Manufacturers'  Mutual  Fire  Insurance  Companies. 
Every  risk  covered  by  these  companies  must  be  protected  by  automatic 
sprinkler  heads.    It  is  impressive  to  note  that  the  19  companies,  com- 
prising what  is  known  as  the  senior  group,  carry  policies  on  industrial 
establishments  aggregating  over  $2,500,000,000;  employed  in  these 
factories  there  are,  as  nearly  as  can  be  ascertained,  about  2,000,000 
people,  and  so  far  as  known  not  a  single  life  has  been  lost  in  any  of  the 
buildings  thus  insured  where  the  sprinkler  heads  were  in  commission 
at  the  time  of  the  fire.    A  few  lives  have  been  lost  in  these  factories, 
but  in  every  such  case  the  fire  gained  headway  because,  for  one  reason 
or  another,  the  automatic  sprinklers  were  out  of  commission  at  the 
time. 

8  The  general  conditions  respecting  factory  insurance  are  apt  to 
surprise  those  who  investigate  them  for  the  first  time.     Among  the 
features  to  be  discovered  is  that  speaking  broadly  the  stock  insurance 
companies  do  not  require  sprinkler  heads,  nor  more  than  a  fractional 
part  of  the  other  safeguards  that  are  required  by  the  Factory  Mutual 
Companies.    In  recent  years  their  leading  men  have  strongly  recom- 
mended sprinklers  and  they  give  great  concessions  in  rates  upon 
sprinkler ed  risks,  but  the  local  agent  of  an  insurance  company,  work- 

1  Trans.  Am.  Soc.  M.  E.,  vol.  35,  pp.  171,  231. 


FRED    J.    MILLER  903 

ing  for  a  percentage  upon  the  premium,  virtually  recommends  that 
his  own  income  be  greatly  reduced  when  he  urges  sprinklers.  Their 
business  is  organized  mainly  with  a  view  to  simply  carrying  at  a 
profitable  premium  rate  the  fire  risk  as  it  is,  and  save  through  such 
agencies  as  their  Factory  Insurance  Association  and  certain  commit- 
tees of  limited  scope,  they  do  little  to  lessen  the  fire  risk  and  thereby 
the  danger  of  loss  of  life. 

9  In  the  case  of  a  typical  factory,  for  instance,  where  the  local 
agent  for  a  stock  company  receives  $200  commission  per  year  on  the 
risk  in  an  unprotected  condition  having  combustible  occupancy,  he 
might  receive  only  $10  if  the  same  building  were  fully  protected 
against  fire  by  automatic  sprinklers,  etc.    There  is,  therefore,  clearly 
no  incentive  for  this  agent  to  inform  the  owner  how  his  fire  risk  and 
the  amount  of  premiums  he  pays  for  insurance  may  be  reduced;  in 
fact  there  is  every  commercial  incentive  in  the  opposite  direction, 
until  "mutual  competition"  threatens  to  take  the  business  entirely 
out  of  his  hands. 

10  It  is  interesting  to  note  that  several  construction  companies 
are  now  offering  to  install  automatic  sprinklers  without  the  payment 
of  any  cost  whatever  by  the  owner,  the  company  making  the  installa- 
tion offering  to  take  as  its  pay  the  difference  between  the  present 
insurance  premiums  and  the  lower  premiums  that  will  be  paid  after 
the  installation  is  made,  for  a  number  of  years  to  be  determined  upon. 
The  meaning  of  this  is  simply  that  the  owner  of  the  building  and  its 
occupants  are  very  much  better  protected  against  fire  without  any  ad- 
ditional outlay,  and  that  at  the  end  of  a  few  years  the  owner  will  have 
the  fire  protective  system  thus  installed  for  his  own,  free  of  cost. 

11  I  do  not  intend  to  advise  either  for  or  against  these  companies, 
but  cite  the  fact  simply  as  conclusive  evidence  of  the  pecuniary  as  well 
as  the  other  advantages  of  automatic  sprinklers. 

12  But  sprinkler  heads  when  once  installed  must  then  be  kept 
ready  for  service  when  needed.    Sprinkler  heads  are  usually  arranged 
in  groups  with  a  supply  pipe  for  each  group.    In  each  of  these  main 
supply  pipes  is  a  valve  by  means  of  which  water  can  be  shut  off  from 
that  section  when  necessary  for  repairs  or  by  reason  of  the  opening 
of  one  or  more  sprinkler  heads,  either  in  performing  its  normal 
service,  or  by  accident.    These  valves  cannot  be  locked  open  because  it 
may  be  necessary  in  an  emergency  to  close  them  as  quickly  as  possible. 

13  These  valves  introduce  an  element  of  danger  and  with  this  it 
is  the  main  object  of  this  paper  to  deal.    The  inspectors  of  the  Mutual 
Companies  frequently  find  the  valves  referred   to  closed,  and  the 


904  CONTROL  OF  AUTOMATIC  SPRINKLER  VALVES 

sprinkler  heads,  therefore,,  of  no  more  use  than  as  though  they  had 
never  been  installed. 

14  In  an  effort  to  lessen  this  evil,  the  Factory  Mutual  Companies 
occasionally  send  to  their  policy  holders  a  circular  letter  on  the  subject 
of  the  danger  of  closed  sprinkler  valves.     In  such  a  report,  covering 
the  months  of  April,  May  and  June  1912,  72  cases  were  reported  where 
inspectors  found  such  valves  closed.   In  63  of  these  cases  the  number 
of  sprinkler  heads  controlled  by  the  closed  valves  are  given,  and  these 
foot  up  to  8274  heads.    Assuming  that  the  cases  in  which  the  number 
of  heads  is  not  given  would  average  about  the  same,  this  means  that 
for  this  report,  covering  three  months,  nearly  10,000  sprinkler  heads 
were  found  out  of  use  by  reason  of  valves  closed  when  they  should 
have  been  open. 

15  In  many  cases  no  reason  was  assigned  for  the  valves  being 
closed,  which  means,  we  may  infer,  that  the  proprietors  did  not  know 
how  the  valves  came  to  be  closed.    It  is  inconceivable,  of  course,  that 
they  would  go  to  the  expense  of  installing  automatic  sprinklers  and 
other  fire  protective 'devices,  and  then  allow  them  to  be  thrown  out  of 
use  if  they  had  the  organization  and  the  discipline  necessary  to  keep 
such  devices  always  available. 

16  The  Remington  Typewriter  Company  owns  and  operates  five 
factories  on  which  it  carries  in  the  Mutual  Companies  insurance  poli- 
cies aggregating  about  $6,000,000.     These  factories  are  protected  by 
nearly  10,000  sprinkler  heads,  the  water  supply  for  which  is  controlled 
by  84  valves. 

17  We  have  had  from  the  start  a  system  of  inspection  under  which 
a  watchman  at  frequent  intervals  examines  each  valve  to  see  whether 
or  not  it  is  open.    If  found  closed,  the  reason  therefor  is  investigated, 
a  report  is  made  and  an  effort  to  prevent  a  repetition  of  the  error. 

18  For  many  years  no  inspector  of  the  Mutual  Companies  had 
found  one  of  our  sprinkler  valves  closed,  until  about  a  year  ago  when 
one  was  found.     The  reason  revealed  by  an  investigation  is  probably 
typical  of  a  good  many  such  cases.    A  mechanic  had  been  making  some 
repairs  in  a  boiler  house,  over  the  boilers,  and  under  the  roof  where 
the  sprinklers  were.     Before  going  up  over  the  boilers  he  closed  the 
valve  controlling  these  sprinklers  as  a  precaution  against  accidental 
flooding.     When  he  had  finished  the  work  he  called  down  to  his 
assistant  to  open  the  valve.    He  took  it  for  granted  that  the  assistant 
had  done  so,  but  for  some  reason  the  valve  was  not  opened  and  the 
next  day  the  inspector  arrived. 


FRED    J.    MILLER 


905 


FIG.  1     SPRINKLER  VALVE  OPEN  WITH  INSTRUCTION  TAG  ATTACHED 


FIG.  2     USE  OF  BED  TAG  ON  CLOSED  SPRINKLER  VALVE 


906  CONTROL  OF  AUTOMATIC  SPRINKLER  VALVES 

19  To  decrease  the  liability  of  valves  being  either  closed  without 
authority,  or  left  closed  when  they  should  have  been  opened,  we  have 
devised  and  have  in  use  in  our  factories  the  system  to  be  described : 

20  Our  sprinkler  valves  are  all  numbered  and  upon  each  valve 
there  is  hung  a  tag  as  shown  in  Figs.  1  and  4.     This  tag  is  marked 
with  the  number  of  the  valve  to  which  it  is  attached,  and,  printed 
upon  the  tag  is  a  prohibition  of  the  closing  of  the  valve  without  a 


*•*•••  ' 


FIG.  3    INDICATOR  BOARD  WITH  HOOK  FOR  EACH  SPRINKLER  VALVE 

signed  permit  to  do  so,  except  when,  in  an  emergency,  or  for  any 
special  reason  it  must  be  closed  at  a  time  when  no  permit  can  be 
obtained,  in  which  case  it  is  to  be  detached  and  hung  upon  a  board, 
shown  in  Fig.  3.  This  is  as  directed  by  the  card  itself,  and  when  it 
is  done  the  blanks  upon  this  card  must  be  filled  in  to  show  by  whom 
the  valve  was  closed,  when  it  was  closed,  and  the  reason  for  closing. 

21     When  such  an  emergency  closing  of  the  valve  takes  place,  at 
a  time  when  the  person  in  charge  of  the  board  (Fig.  3)  is  away,  the 


FRED    J.    MILLER 


907 


watchman  or  other  person  having  access  to  it  goes  to  the  board  with 
the  person  who  has  closed  the  valve.  Both  these  men  then  see  that 
a  red  card  complete  but  left  blank  is  hung  upon  the  board  over  the 
card  removed  from  the  closed  valve.  These  are  hung  upon  the  hook 


o 

SPRINKLER    VALVE 


DO  NOT  CLOSE  THIS  VALVE 
UNTIL  A  SIGNED  PERMIT  IS  SE- 
CURED FROM  THE  WORKS  ENGIN- 
EER'S OFFICE, 

EXCEPT 

IT  BECOME  NECESSARY  AT  A  TIME 
WHEN  SUCH  PERMIT  CAN  NOT  BE 
GIVEN, 

WHEN 

THE  ONE  IN  CHARGE  OF  THE 
WORK  BEING  DONE  IS  INSTRUCT- 
ED TO  REMOVE  THIS  TAG,  SIGN, 
DATE  AND  GIVE  REASON  FOR 
CLOSING,  TAKE  AT  ONCE  TO  THE 
WORKS  ENGINEER'S  OFFICE  AND 

PLACE   ON    HOOK    NUMBER OF 

THE    SPRINKLER    VALVE    BOARD. 


OPEN    VALVE    AS    SOON    AS    WORK 
WILL   PERMIT. 


REASON   FOR  CLOSING 


DATE 


SIGN    NAME. 


FIG.  4    INSTRUCTION  TAG  ATTACHED  TO  EVERY  SPRINKLER  VALVE 

numbered  to  correspond  with  the  number  of  the  closed  valve.  These 
cards  thus  hung  upon  this  hook  are  intended  to  attract  the  notice  of 
the  person  having  the  board  in  charge,  who  will,  after  proper  investi- 
gation, fill  out  the  blanks  on  the  red  card,  hang  the  lower  portion  of 
it  on  the  numbered  hook  corresponding  to  the  closed  valve,  and  attach 


908  CONTROL   OF  AUTOMATIC   SPRINKLER  VALVES 

the  upper  portion  to  the  valve  itself,  as  shown  in  Fig.  2,  unless  it  shall 
have  previously  been  re-opened. 

22  In  most  cases  it  will  be  possible  to  obtain  a  written  permit 
before  closing  a  valve,  and  in  such  case  the  permit  is  given  by  the 
person  in  charge,  by  filling  in  the  blanks  printed  upon  the  red  tag 
(Fig.  5).     It  is  then  torn  in  two  at  the  dotted  line,  and  the  upper 
portion  of  it  given  to  the  person  applying  for  the  permit,  who  attaches 
it  to  the  valve  before  closing  it  (Fig.  2).     The  lower  portion  of  the 
same  red  tag  is  hung  upon  the  hook  numbered  to  correspond  with  the 
number  of  the  valve,  as  shown  by  Fig.  3. 

23  The  board  is  fastened  to  the  wall  of  the  room,  or  above  the 
desk  of  the  person  having  the  system  in  charge,  who  may  be  the  chief 
engineer,  the  superintendent,  or  one  of  his  assistants,  and  the  red  tag 
hanging  upon  the  hook  is  a  constant  reminder  to  him  and  a  token  to 
all  others  who  may  be  interested,  that  the  valve  is  closed.     During 
this  time  the  valve  itself  will  have  hanging  upon  it  the  red  permit 
tag,  as  shown  by  Fig.  2,  which  is  a  sign  and  reminder  so  long  as  it 
remains  there  that  the  valve  is  closed  and  that  the  sprinkler  heads 
controlled  by  it  are  therefore  out  of  commission. 

24  It  will,  of  course,  be  perceived  that  the  main  feature  of  this 
system  is  the  board  with  numbered  hooks,  which  is  in  plain  view  of 
the  factory  official  charged  with  responsibility  for  the  sprinkler  valves; 
a  red  tag  upon  this  board  is  a  danger  signal,  which  means  it  should 
be  taken  off  as  soon  as  possible,  and  this  can  be  done  only  by  re- 
opening the  valve.     The  card  has  written  upon  it  the  time  at  which 
it  was  expected  that  the  valve  could  be  re-opened.    It  is  the  business 
of  the  official  having  the  board  in  charge,  when  this  specified  time  has 
passed;  to  investigate  the  reason,  and  if  a  later  time  must  be  assigned 
to  indicate  it  upon  the  card  and  again  take  it  up. 

25  While  the  description  of  this  procedure  may  make  it  seem 
somewhat  formidable,  in  actual  operation  it  is  not  at  all  inconvenient, 
and   it  gives   to   some  responsible  person   control   of   the   sprinkler 
valves. 

26  Of  course  this  system  of  valve  control  is  not  presented  under 
the  impression  that,  by  itself  considered,  it  is  a  wonderful  invention. 
So  far  as  that  is  concerned  it  is  no  more  than  is  being  done  every  day 
for  the  accomplishment  of  various  objects.     It  was  devised  to  over- 
come a  difficulty  which,  in  view  of  all  the  conditions  now  existing, 
it  seems  rather  important  to  eliminate  in  factories  generally  where 
sprinklers  have  been  installed;  it  can  save  property  from  destruction 
by  fire  and  may  easily  save  the  lives  of  those  employed  in  factories ;  for 


FRED    J.    MILLER  909 

that  reason  it  is  here  presented.  It  was  not  devised  by  myself  alone, 
but,  in  accordance  with  the  regular  practice  in  our  organization,  the 
idea  of  it  was  presented  to  all  our  factories  and  it  was  then  developed 
and  perfected  by  the  suggestions  of  the  superintendents  of  those 
factories,  Messrs.  E.  E.  Barney,  G.  B.  Brand,  W.  N.  Brand,  all  of 
whom  are  members  of  the  Society,  and  Mr.  C.  W.  Burges. 

27  Mr.  John  R.  Freeman  thought  so  well  of  it  that  it  has  been 
recommended  by  the  Mutual  Companies,  including  those  of  which  he 
is  president,  and  his  associates  have  added  some  improvements  to  the 
red  card,  notably  by  arranging  it  so  that  the  coupon  which  has  been 
hung  upon  the  board  to  signify  a  closed  valve  goes,  when  the  valve  is 
opened,  to  the  superintendent,  who  is  thus  enabled  to  know  how  much 
of  valve  closing  is  taking  place,  and  the  reasons  for  it.  This,  I  be- 
lieve, is  an  excellent  feature.  The  cards  are  now  being  supplied  to  all 
policy  holders  in  the  Mutual  Companies  and  a  reproduction  of  them 
is  shown  in  Figs.  5  and  5a. 

2$  In  some  of  our  factories,  there  are  certain  valves  which,  with 
the  approval  of  the  mutual  companies  are  closed  during  the  winter 
months.  As  it  was  thought  to  be  undesirable  that  a  red  card  should 
hang  upon  the  board,  as  shown  by  Fig.  3,  for  some  months,  because 
clanger  signals  constantly  displayed  are  apt  to  cease  to  convey  the 
idea  of  danger,  they  have  proposed  in  one  of  our  factories  to  cover 
the  red  card  hung  upon  the  boarcl  under  such  circumstances  by  a 
green  card.  That  may  be  the  best  way  to  do  it,  but  I  am  inclined 
to  think  that  a  better  way  is  to  leave  off  the  red  card  entirely  from 
the  board  and  to  put  a  memorandum  into  a  tickler  file  so  that  the 
matter  of  reopening  the  valve  will  be  automatically  presented  to  the 
person  in  charge  upon  a  predetermined  date.  This  memorandum  may 
appropriately  be  one  of  the  white  cards  shown  in  Fig.  4  properly  filled 
out ;  but  the  red  tag  should  in  all  cases  be  hung  upon  a  closed  valve. 

29  Mr.  Freeman  does  not  think  so  well  of  the  white  card.  We 
use  it  because  by  means  of  it,  always  hanging  upon  a  valve,  a  person 
whose  business  it  may  be  to  close  a  valve  can  learn  and  become  familiar 
with  what  else  is  required  of  him  besides  merely  closing  a  valve  and 
then  perhaps  forgetting  it.  In  the  interest  of  the  life-saving  feature, 
the  Remington  Typewriter  Company  will  supply  such  cards  free  to 
all  who  may  wish  to  use  them.  Some  are  printed  upon  cloth  for  use 
when  valves  are  out  of  doors,  others  upon  cardboard.  With  the  cards 
thus  supplied  it  will  be  necessary  only  for  the  factory  to  provide  for 
itself,  the  board  with  ordinary  screwed  brass  hooks,  numbered  as 
shown — to  put  the  board  up  before  the  eyes  of  a  responsible  factory 


910 


CONTROL  OF  AUTOMATIC  SPRINKLER  VALVES 


(SEE   OTHER  SIDE) 


O 


FIRE 


SPRINKLERS     SHUT 


Attach  this  Tag  to  Valve 


IEverySprinklerValve  should  be  numbered, pre- 
ferably with  white  paint  figures  at  least  2 
inches  tall.  May  be  on  pipe  close  to  valve. 

Shut  on...  ..191  .       .M 

Day  of  Week-     Month       Date  Hour 

By 

To  be  shut  Name  of  man  who  shut  the  valve 

Only  until ...  ..191.      ..M. 

Day         Month          Date  Hour 

Reason  for  Closing 

Closing  Authorized  by 

TagNo 

Signature  of  Master  Mechanic  or  other  official 
Don't  remove  this  tag  until  valve  Is  opened.    If  valve 
is  not  opened  at  above  time,  fill  out  and  attach  a  second 
tag  extending  time;  also  a  third  tag  if  need  be. 

Opened  On..... .. 191 M. 

Day         Month         Date  Hour 

f  After  opening  valve  take  this  tag  to  Mas- 
'  •{  ter  Mechanic's  Office  to  be  kept  until 

Uy [  next  Insurance  Inspector's  visit. 

Signature  of  man  who  opened  valve 

This  Coupon  is  to  be  torn  off  and  hung  on  conspicu- \ 
ous  peg  board  in  Master         Mechanic's  Office  until  tag 
is  returned  signed  by  the  CJ  man  who  opened  valve. 

After  return  of  tag,  en-        ter  date  of  opening  on  this 
coupon,  and  send  it  to  General  Superintendent's  Office. 

FIRE   SPRINKLERS  ARE   SHUT  OFF 
In 

Name  of  Building  and  room 

At  Valve  No on 191  . 

Day        Month        Date 

By 

To  be  shut  Name  of  man  who  shut  the  valve 

Only  until..... 191  M. 

Day          Month          Date 

Reason  for  Closing 

Closing  Authorized  by 

TagNo 

Signature  of  Master  Mechanic  or  other  official 

Opened  by on        ....  191  . 

Name  of  man  who  opened  valve  Date 

(SEE   OTHER  SIDE) 


FIG.  5    FORM  OF  BED  CARD  USED  BY  THE  MUTUAL  COMPANIES 


FRED    J.    MILLER 


911 


(SEE   OTHER  SIDE) 


O 


The  danger  of  greatest  loss  from  Fire  in  facto- 
ries insured  in  "The  Mutuals"  to-day  comes  from 
Sprinkler  Valves  improperly  closed  or  forgotten. 

On  almost  every  day  the  insurance  inspectors 
find  somewhere  an  important  Sprinkler  Valve 
shut.  Often  this  occurs  in  factories  which  take 
pride  in  their  order  and  discipline. 

RULES. 

1.  Sprinkler  valves  must  not  be  closed  without 
authority  frdm  the  Master  Mechanic  or  other 
official,  except  in  case  of  accident,  when  no- 
tice   must    be    sent    at    once    to    the    Master 
Mechanic. 

2.  A  tag  must  be  filled  out  and  attached  to  the 
valve   (inside  or  yard)   every  time  a  valve   is 
closed. 

3.  Never  shut  off  more  sprinklers  than  necessary, 
and  keep  off  only  for  shortest  possible  time. 

4.  Provide  for  immediate  turning  on  of  water  in 
case  of  fire.    Where  large  values  are  involved 
keep   a   man   near  the  closed   valve   ready  to 
open  it  on  notice. 

5.  For  long  and   important  shut  offs  provide  ex- 
tra   watchman    to    patrol    shut    off    area    and 
notify   Insurance  Companies. 


O 

The  Master  Mechanic  or  Superintendent 
should  provide  in  his  office  a  conspicuous  board 
with  hooks,  for  these  danger  signals,  and  with 
supply  of  extra  cards.  Preferably  a  white  board 
with  a  red  border  marked  at  the  top — 
"NOTICE  OF  FIRE  SPRINKLERS  SHUT  OFF." 

This  method  of  Coupon  Danger  Cards  was  in- 
vented and  tested  in  the  Remington  Typewriter 
Works  and  appears  to  be  the  best  yet  devised. 
Its  adoption  everywhere  is  urged  by  the  Associ- 
ated Factory  Mutual  Fire  Insurance  Companies. 


A  supply  of  these  tags  should  be  kept  in  Master  Mech- 
anic's Office,  and  may  be  obtained  free  of  cost  from  the 
Associated  factory  Mutual  Fire  Insurance  Companies, 
Inspection  Department,  31  Milk  Street,  Boston. 

A  few  spare  tags  for  emergency  use  should  be  kept  con- 
spicuously placed  near  desk  of  head  of  each  department. 


FIG.  5a  EEVERSE  OF  MUTUAL  COMPANIES  '  EED  CARD 


912  CONTROL  OF  AUTOMATIC  SPRINKLER  VALVES 

official,  and  then  to  see  that  the  system  is  used.  And  it  is  safe  to  say 
that  if  an  owner  finds  that  this  or  some  such  system  cannot  be  main- 
tained in  effective  operation,  it  may  be  taken  as  a  symptom  of  the  need 
of  better  organization  in  that  factory. 

DISCUSSION 

GEORGE  I.  ROCKWOOD.  As  Mr.  Miller  points  out  in  his  very  inter- 
esting paper,  the  possibility  of  the  unauthorized  closure  of  automatic 
sprinkler  system  shut-off  valves  is  the  only  remaining  nightmare  be- 
fore the  eyes  of  fire  protection  experts.  In  view  of  the  record  of  fire 
losses  due  to  such  unauthorized  or  accidental  shutting  off  of  the  water 
supply  to  sprinkler  systems,  it  is  singular  that  so  little  has  been  done 
to  give  any  automatic  protection  against  such  a  possibility.  All  the 
rest  of  the  apparatus,  such  as  the  sprinkler  head,  the  alarm  valve,  the 
dry  pipe  valve,  and  the  system  of  sprinkler  piping,  has  been  developed 
to  a  high  pitch  of  perfection;  but  this  one  point  remains  to  be 
developed. 

Impressed  with  the  importance  of  this  problem,  I  have  invented 
and  developed  a  simple  and  inexpensive  piece  of  mechanical  and 
electrical  apparatus  designed  to  supplement  the  very  suggestions  con- 
tained in  Mr.  Miller's  paper.  Mr.  Miller  desires  the  master  mechanic, 
or  the  person  in  charge  of  the  sprinkler  systems  in  an  establishment, 
to  divide  a  printed  card  in  the  middle,  fill  out  on  each  half  the  reason 
for  closing  the  shut-off  valve  and  the  time  when  it  may  be  expected 
to  be  opened  and  the  pressure  restored  to  the  system  again,  and  then 
requires  him  to  tie  one:half  of  the  broken  card  to  the  stem  of  the  gate 
valve  and  to  carry  the  other  half  into  the  office  and  leave  it  with  some 
authorized  person  who  shall  share  with  him  the  responsibility  for 
shutting  off  the  water  supply. 

This  system  would  be,  of  course,  entirely  satisfactory  provided  the 
person  who  is  required  to  carry  it  out  really  does  so.  It  does  not  take 
very  much  imagination,  however,  to  suggest  many  everyday  reasons 
why  it  would  be  for  the  interests  of  such  a  person  to  omit  such  notice 
altogether,  in  which  event  there  is  a  large  possibility  that  the  valve 
may  be  left  shut,  whether  intentionally  or  inadvertently,  for  a  long 
period  of  time.  For  example,  a  workman  may  go  home  to  luncheon 
at  noon  leaving  the  valve  shut,  and  something  may  interfere  with  his 
return;  if  the  job  is  to  be  done  at  night,  or  the  job  of  repairing  the 
sprinkler  system  extends  into  the  evening,  the  person  notified  by  the 
other  half  of  the  card  may  be  absent  until  the  next  day,  in  which  case 


DISCUSSION  BY  G.  I.  ROCKWOOD  913 

it  might  easily  be  that  the  valve  would  be  left  shut  at  least  until  his 
return. 

The  device  which  I  have  developed  makes  it  necessary  for  the 
master  mechanic  to  attach  his  card  directly  to  an  electric  switch  that 
controls  an  electric  bell,  which  switch  must  be  opened  before  he  can 
attach  it,  and  cannot  be  left  open  without  the  aid  of  a  second  person. 
This  second  person  should  be  the  one  relied  upon  to  se*e  that  the  valve 
is  actually  reopened  at  the  appointed  time.  He  is  also  the  one  who 
would  pay  attention  in  case  the  valve  was  shut  by  some  unauthorized 
person  who  had  not  first  gone  through  the  process  of  notifying  the 
man  in  the  office,  and  getting  his  assistance  in  holding  the  switch 
open,  as  this  would  result  in  turning  in  an  alarm  directly  in  the  office. 
The  way  this  is  effected  is  by  attaching  an  electric  circuit  closer  to 
the  valve  stem  of  the  main  shut-off  valve  in  a  way  such  that  any 
motion  of  the  valve  stem  in  the  direction  of  shutting  the  valve  will 
immediately  cause  the  circuit  closer  to  close  the  electric  circuit  through 
the  alarm  bell  and  the  red  light  in  the  office. 

When  the  switch  is  opened  through  an  arc  of  180  deg.  it  will  be 
held  open  provided  the  master  mechanic  has  caused  the  circuit  closer 
on  the  valve  stem  to  close  by  shutting  the  valve ;  but  this  would  result 
in  an  alarm  in  the  office  if  the  assistance  of  the  man  who  is  to  be 
notified  that  the  valve  is  to  be  shut  lias  not  actually  been  obtained  to 
hold  the  controlling  switch  clear  open  against  an  electric  magnet 
energized  by  the  same  current  that  lights  the  light  and  rings  the  bell, 
while  the  other  man  goes  to  the  sprinkler  riser  and  shuts  the  valve. 

It  will  be  observed  that  this  mechanical  and  electric  supervisory 
system  is  entirely  supplementary  to  the  system  proposed  by  Mr.  Miller, 
that  it  does  not  interfere  with  it  in  the  slightest  degree,  and  that  its 
influence  is  positive  if  it  actually  works  as  intended,  but  that  if  it 
should  fail  to  work  there  would  be  no  interference  with  the  operation 
of  the  simple  card  scheme.  This  system  has  been  in  operation  in  my 
own  factory  for  several  months,  has  been  demonstrated  to  various 
underwriters,  and  seems  to  be  quite  satisfactory.  No  doubt  about  its 
operation,  either  theoretically  or  actually,  has  thus  far  developed. 

The  principle  covering  the  development  of  this  device  is  that  more 
than  one  man  should  have  something  to  say  about  the  opening  and 
shutting  of  sprinkler  valves,  and  that  the  operations  of  the  extra 
person  should  be  mechanically  interlocked  with  those  of  the  person 
directly  charged  with  the  oversight  of  the  sprinkler  system.  The 
device  in  question,  in  addition  to  being  supervisory  over  the  motions 


914  CONTROL  OF  AUTOMATIC  SPRINKLER  VALVES 

of  the  shut-off  valves,  is  also  a  fire  alarm  and  a  water  pressure  alarm. 
In  regard  to  the  latter  point,  it  may  be  said  that  the  bell  will  ring 
and  the  light  will  light  if  the  water  pressure  falls  beyond  a  certain 
predetermined  point. 

In  the  history  of  sprinkler  systems  it  has  frequently  happened 
that  main  shut-off  valves  have  been  shut  with  a  heavy  hand  and  then 
apparently  opened  again,  when,  in  reality,  it  was  subsequently  found 
out  that  the  only  part  of  the  valve  which  opened  was  the  stem,  which 
had  become  detached  from  the  plug.  This  may  easily  happen  when 
the  valve  stem  is  shut  with  a  big  wrench  in  an  outside  gate  and  the 
stem  is  twisted  after  the  valve  has  bedded  upon  its  seat.  In  such  a 
case  as  that,  my  alarm  system  would  call  the  fact  to  the  attention  of 
the  office  automatically. 

JAMES  P.  TOLMAN.  It  appears  to  me  that  Mr.  Miller's  instruction 
tag  does  not  afford  all  the  protection  that  is  possible.  In  our  mill  we 
have  used  a  tag  similar  in  style  to  that,  but  in  place  of  the  circular 
hole  we  have  a  slotted  hole,  through  which  is  passed  a  piece  of  lace 
leather.  The  leather  is  also  passed  through  the  yoke  and  the  arm  of 
the  hand  wheel,  which  seals  the  valve.  The  lace  leather  is  secured  by 
a  tubular  rivet,  easily  applied.  Each  valve  which  controls  sprinklers 
throughout  the  mill  is  always  sealed,  either  open  or  shut.  If  it  is  a 
valve  which  should  be  closed  in  winter,  it  is  sealed  shut.  If  it  is  a 
valve  which  should  be  open  at  all  times,  it  is  always  sealed  open,  and 
the  tag  requires  any  person  breaking  the  seal  to  take  the  tag  to  the 
office.  Recently  the  Mutual  Insurance  Companies  have  been  sending 
out  the  tag  shown  in  the  latter  part  of  the  paper,  and  we  felt  that  it 
was  an  improvement  and  adopted  it.  But  we  also  retain  our  old  form 
of  tag,  which  we  now  make  from  green  card,  and  this  green  tag  is 
on  every  normally  conditioned  valve  at  all  times,  showing  that  the 
valve  is  sealed,  and  that  persons  who  break  the  seal  of  the  valve  are 
to  take  the  tag  immediately  to  the  office.  If  a  valve  has  its  seal 
broken,  there  is  a  notice.  The  red  tag  has  supplanted  the  green  tag, 
and  every  valve  should  always  have  one  or  the  other  tag  upon  it. 

One  of  the  objections  made  by  Mr.  Rock  wood  to  the  tag  is  that 
when  a  valve  was  marked  with  a  red  tag,  it  would  never  be  seen  by 
anybody  unless  he  happened  to  see  it.  I  want  to  say  that  it  is  the 
practice  of  all  the  mutually  insured  mills  to  have  weekly  inspections 
of  the  fire  protective  system.  We  have  different  men  inspect  the 
system  for  different  periods  of  time.  If  a  valve  is  wrongly  marked, 


DISCUSSION  915 

having  the  red  tag  instead  of  a  green  tag,  it  will  be  brought  to  the 
attention  of  the  superintendent  at  least  as  soon  as  Monday  morning. 

GORHAM  DANA.1  I  agree  with  the  previous  speakers  that  the 
matter  of  a  closed  valve  in  the  sprinkler  system  is  a  most  vital  point 
in  the  matter  of  fire  protection  in  sprinkler-equipped  plants.  If  we 
could  eliminate  the  unnecessarily  closed  valve,  the  fire  loss  would  be 
very  materially  reduced. 

The  scheme  which  one  of  the  speakers  proposed  is  an  admirable 
one  for  certain  conditions,  but  it  does  not  seem  to  cover  our  condi- 
tions. In  order  to  succeed  with  such  a  plan,  it  is  necessary  that  a 
plant  should  be  extremely  well  managed,  with  an  efficient  master 
mechanic  and  an  efficient  superintendent.  There  are  a  good  many 
plants  equipped  with  automatic  sprinklers  that  do  not  have  these  con- 
ditions, a  great  many  tenant  factories,  and  a  great  many  New  York 
loft  buildings,  where  there  are  many  different  firms  in  the  building, 
and  where  it  is  difficult  to  get  at  any  one  to  care  for  the  sprinkler 
system.  There  are  a  great  many  small  plants  in  various  towns  and 
cities  that  have  no  master  mechanic  who  is  worthy  of  the  name,  where 
the  problem  is  very  different. 

The  organization  with  which  I  am  connected  has  been  working 
on  this  problem  for  a  number  of  years,  and  we  have  solved  it  in  rather 
a  different  manner,  which,  to  my  mind,  covers  cases  which  this  scheme 
would  not  cover.  The  plan  is  to  have  the  valve  fastened  by  the  in- 
surance inspectors.  The  tag  which  is  used  (Fig.  6)  is  slipped  over  the 
seal  and  is  used  in  case  the  seal  is  broken  to  notify  the  insurance  com- 
pany. That  is  to  say,  the  tag  is  similar  to  the  one  shown  here,  but 
somewhat  differently  worded,  and  in  case  the  seal  has  to  be  broken  to 
close  the  valve,  the  person  who  breaks  the  seal  fills  out  certain  data  as 
to  the  circumstances  (the  reason  for  closing  the  valve,  etc.,  the  present 
condition  of  the  valve,  whether  it  was  opened  at  once  or  not)  and  this 
information  is  put  on  the  back  of  the  tag  and  the  tag  mailed  to  the 
insurance  inspection  department.  We  find  it  to  be  extremely  necessary 
in  any  plant  which  has  not  an  efficient  management,  to  have  this 
information  sent  to  the  insurance  interests. 

Mr.  Rockwood's  scheme  is  a  very  excellent  one,  and  I  trust  it  will 
come  into  general  use,  but  it  has,  however,  one  drawback:  if  a  valve 
is  closed  for  any  length  of  time  the  alarm  does  not  do  much  good.  If 

1  Manager,  The  Underwriters'   Bureau  of  New  England,   141    Milk  Street, 
Boston,  Mass. 


916 


CONTKOL  OF  AUTOMATIC  SPRINKLER  VALVES 


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DISCUSSION  917 

a  valve  is  closed  for  repairs,  for  an  hour  or  two  hours,  you  have  got 
to  shut  of?  the  alarm  and  cannot  have  it  ringing  all  the  time,  and  for 
that  reason  some  notification  to  the  people  most  vitally  interested,  the 
insurance  companies,  is  most  desirable  in  my  opinion. 

W.  H.  KENERSOX  (written).  There  can  be  no  difference  of  opinion 
in  regard  to  the  necessity  for  keeping  all  sprinkler  valves  open,  and 
if  it  is  impossible  to  provide  some  of  the  mechanical  supervisory  de- 
vices, the  scheme  outlined  in  the  paper  is  highly  desirable.  I  take  it 
that  the  purpose  of  the  paper  it  to  put  before  the  public  a  scheme 
which  anybody  can  employ,  and  the  description  of  the  system  is  in 
such  detail  that  I  beg  to  suggest  one  further  simple  expedient  which 
will  make  it  more  effective.  The  majority  of  us  have  probably  had 
difficulty,  when  using  a  system  employing  tags  hanging  on  open  hooks, 
in  keeping  the  tags  in  place  because  of  drafts,  careless  handling,  etc. 
The  simple  expedient  of  turning  the  hooks  upside  down,  will  almost 
entirely  obviate  the  difficulty.  Such  an  arrangement  would  make 
this  system  much  more  reliable. 

CHARLES  H.  BIGELOW.  While  I  believe  the  tag  is  a  good  thing, 
exceptional  discipline  is  required  to  keep  it  up  in  every  case,  especially 
in  places  having  only  a  small  mechanical  force  of  the  class  often 
employed,  and  where  the  office  is  a  long  distance  from  the  valves. 
There  the  tendency  would  be,  especially  for  a  short  job,  for  the  man  to 
shut  off  the  valve  and  do  the  work,  instead  of  taking  the  tag  to  the 
office,  returning  to  do  the  work  and  then  going  back  to  the  office  after 
the  tag,  particularly  as  many  of  them  regard  such  regulations  as  "red 
tape"  if  they  think  of  them  at  all.  The  trouble  is,  however,  that  while 
the  men  may  open  up  the  valve  in  most  cases,  there  is  always  the 
chance  of  the  man  being  called  away  and  forgetting  to  open  the  valve, 
so  that  probably  the  tag  system,  even  if  not  kept  up  the  way  it  should 
be,  would  be  a  help. 

POMEROY  W.  POWER  (written).  The  weekly  inspection  seems  to 
be  a  very  good  system  to  use  in  connection  with  any  method  of  keeping 
track  of  sprinkler  valves.  Our  plan  is  giving  good  results.  Every 
Thursday  an  inspector  examines  each  indicator  post  gate  and  signs 
a  tag,  which  is  attached  to  the  post,  with  his  name  and  the  date. 
After  his  examination  of  all  sprinkler  valves,  the  inspector  signs  a 
typewritten  form  of  letter,  which  reads  something  like  this :  "I  have 
this  day  inspected  all  of  the  sprinkler  valves.  They  are  all  open  and 


918 


CONTROL  OF  AUTOMATIC  SPRINKLER  VALVES 


TABLE  1     INSPECTION  RECORD  OF  HOSE  HOUSES  AND  SPRINKLER 

VALVES 

Andrew  McLean  Co.,  Passaic,  N.  J. 

Sizes  State  of 
Location                                                                  In.  Valve 

1  Third  St.,  gate  valve,  city  connection 6  Open 

2  Mill  No.  1,  napping  depart.,  indicator  post 6  Open 

3  Mill  No.  1,  napping  department,  drip 2  Closed 

4  Hose  house  No.   1,  two-way  hydrant,       ft.  hose       washers,  Clear 

spanners,          nozzle. 

5  Boiler  house,  sprinkler  line .  .3  Open 

6  Boiler  house,  sprinkler  drip 1  y2  Closed 

7  Boiler  house,  6-in.  gate  in  line  to  mill  No.  1 6  Open 

8  Old  boiler  house,  drip 2^  Closed 

9  Old  boiler  house,  sprinklers  under  gallery 2  Open 

10  Kier  room,  kier  dye  and  breach  room  sprinklers 3^  Open 

11  Kier  room,  drip  for  above 1  ^  Closed 

12  Old  grey  room,  drip 2  Closed 

13  Mill  No.  1,  second  floor  sprinklers  for  tower 1%  Open 

14  Mill  No.  1,  indicator  post  (tower  entrance) 6  Open 

15  Mill  No.  1,  indicator  post  (shipping  room) 6  Open 

16  Drip  in  shipping  room 1 1^  Closed 

17  Hose  house  No.  2,  one-way  hydrant,       ft.  hose       washers,  Clear 

spanners,          nozzle. 

18  Storehouse  No.  2,  indicator  post 6  Open 

19  Storehouse  No.  2,  basement  drip 2  Closed 

20  Office,  indicator  post 6  Open 

21  Office,  drip  in  pit  of  1st  toilet 2  Closed 

22  6-in.  valve  in  main  rear  shop 6  Open 

23  Storehouse  No.  3,  basement  drip 2  Closed 

24  Storehouse  No.  3,  two-story  end,  indicator  post 6  Open 

25  Storehouse  No.  3,  two-story  end,  drip 2  Closed 

26  Storehouse  No.  3,  one-story  end,  indicator  post 6  Open 

27  Hose  house  No.  3,  two-way  hydrant,       ft.  hose       washers,  Clear 

spanners,          nozzle. 

28  Hose  house  No.  4,  two-way  hydrant,       ft.  hose       washers,  Clear 

spanners,          nozzle. 

29  Hose  house  No.  5,  two-way  hydrant,       ft.  hose       washers,  Clear 

spanners,          nozzle. 

30  Mill  No.  2,  indicator  post 6  Open 

31  Mill  No.  2,  drip 2^  Closed 

32  Hose  house  No.  6,  two-way  hydrant,       ft.  hose       spanners,  Clear 

washers,          nozzle. 
The  above  has  been  examined  by  me  to-day. 

Date, Signed, 

Countersigned  by 


DISCUSSION  919 

in  good  order,  except Under  the  list  of  exemptions  he  fills  in 

the  location  of  any  valve  that  is  closed,  the  date  when  it  was  closed 
and  the  date  that  it  is  expected  to  be  opened.  That  letter,  after  being 
signed  by  the  inspector,  is  sent  to  the  manager  as  a  weekly  report. 
After  about  four  years  use  of  this  plan,  we  have  had  only  one  case  of 
a  valve  being  found  closed. 

LEWIS  H.  KtnsTHABDT.  This  whole  question  comes  down  to  a 
matter  of  responsibility.  iSome  one  must  be  made  absolutely  re- 
sponsible in  a  plant  for  the  maintenance,  for  instance,  of  the  sprinkler 
valves,  the  same  as  some  one  must  be  made  responsible  for  the  main- 
tenance of  any  other  piece  of  apparatus  in  the  plant.  A  combination 
of  the  inspection  and  the  tag  will,  we  believe,  fulfill  these  conditions 
of  keeping  the  valves  open.  Of  course,  there  is  a  fair  possibility  that 
something  may  slip  up,  but  when  it  does  slip  up,  the  point  is  that  you 
must  have  some  responsible  person  to  whom  to  look  to  see  why  it 
occurs,  and  that  it  does  not  occur  again.  Any  one  who  tries  this 
combined  plan,  that  is,  a  system  of  inspection  and  tagging  the  valves, 
will  accomplish  the  result. 

F.  J.  BRYANT  (written).  At  our  plant  we  have  inspection  cards 
giving  in  itemized  detail  the  route  to  be  followed,  showing  the  location, 
size,  type  and  duty  of  each  valve,  the  location  of  each  length  of  hose, 
each  nozzle,  tool,  etc.,  as  shown  in  Table  1.  The  man  making  the 
inspection  takes  the  card  and  checks  each  item  as  he  comes  to  it  (if 
he  finds  it  correct)  and  notes  any  discrepancies  on  the  margin.  After 
completing  the  round  he  signs  the  card,  as  the  previous  speaker  said, 
and  places  it  upon  the  manager's  desk,  who  countersigns  it  and  has  it 
filed  for  further  reference. 

THE  AUTHOR.  Before  adopting  this  system  of  cards,  we  carefully 
considered  mechanical  and  electrical  devices  for  controlling  our  valves. 
There  are  men  in  our  organization  who  have  devoted  a  great  deal  of 
study  to  electrical  devices  and  they  at  once  thought  of  like  means  of 
controlling  valve  opening  and  closing,  and  proposed  several  schemes. 
We  have,  after  careful  study  of  the  matter,  come  to  the  conclusion 
that  it  is  better  to  depend  upon  our  discipline  and  organization  and 
to  have  some  one  responsible  for  these  valves.  If  we  put  a  mechanical 
or  electrical  device  on  the  valves,  any  one  would  still  be  able  to  close 
it  at  will,  and  it  would  not  involve  the  doing  of  anything  else.  We 
believed  that  notwithstanding  the  use  of  such  a  device  we  would  have 


920  CONTROL  OF  AUTOMATIC  SPRINKLER  VALVES 

to  go  to  some  form  of  tag  and  report  in  addition.  It  is  a  fact  that 
any  automatic  device,  such  as  a  water  level  indicator  in  a  boiler,  or 
anything  of  that  sort,  that  is  depended  upon  to  indicate  danger  or 
abnormal  conditions  is  apt  to  be  depended  upon  too  much;  some  day 
it  will  not  work  and  then  there  is  disaster.  For  our  conditions  at  any 
rate,  a  thoroughly  organized  system  for  taking  care  of  these  valves  and 
a  definite  placing  of  responsibility  upon  someone  for  their  condition 
is  the  best.  The  seal  idea  for  the  card  seems  to  be  good,  and  would  be 
a  useful  addition  to  it. 

We  had,  as  stated  in  the  paper,  before  this  card  sj^stem  was  in- 
stalled, a  very  thorough  system  of  inspection  for  these  valves,  and  we 
still  maintain  that  inspection  system.  But  the  trouble  about  a  weekly 
inspection  is  that  if  the  inspector  looks  at  a  valve  on  a  Thursday 
morning,  the  valve  may  be  closed  until  the  .next  Thursday  morning 
and  no  one  know  anything  about  it  except  the  man  who  closed  it.  Our 
system  provides  that  someone  must  know  about  it;  some  responsible 
person  must  know  immediately  if  the  valve  is  closed,  and  we  think 
that  is  important.  Of  course,  there  must  be  discipline,  a  definite 
placing  of  responsibility  and  strict  accountability. 


No.  1423 

THE  NEED  OF  MORE  CARE  IN  THE  DESIGN 

AND  CONSTRUCTION  OF  ELEVATED 

TANKS 

BY  W.  O.  TEAGUE,  BOSTON,  MASS. 
Member  of  the  Society 

The  elevated  or  gravity  tank  for  fire  protection  systems  has  been 
from  the  first  an  important  limited  secondary  source  of  water  supply, 
and  its  value  has  increased  greatly  with  the  increase  in  number  and 
size  of  tanks  installed  generally  throughout  the  country,  especially  in 
those  cities  and  districts  where  the  public  water  supply  is  of  low 
pressure,  as  is  the  case  in  Philadelphia.  The  tanks  are  usually  located 
above  buildings  in  cities  and  on  detached  towers  in  the  country.  A 
typical  detached  structure  is  shown  in  Fig.  1,  which  is  a  150,000-gal. 
tank  on  a  242-ft.  tower  at  the  plant  of  the  New  York  Shipbuilding 
Company,  Camden,  N.  J. 

2  The  tanks  were  first  made  of  wood,  but  there  are  now  as  many 
being  made  of  steel.    Wooden  tanks  have  been  built  up  to  100,000  gal. 
capacity,  although  they  are  rarely  larger  than  60,000  gal.,  for  above 
this  capacity  the  steel  tank  is  cheaper  and  more  practicable.    The  cost 
of  a  60,000-gal.  tank  of  wood  or  steel  erected  on  a  75-ft.  steel  tower 
is  about  $3,000.    Steel  tanks  are  built  in  large  sizes,  one  of  the  largest 
being  of  1,200,000  gal.  capacity;  this  one  is  50  ft.  in  diameter  and  90 
ft.  high,  and  is  supported  by  a  steel  tower  130  ft.  high. 

3  Failures  of  tanks  in  service,  involving  loss  of  life  and  destruc- 
tion of  property,  have  shown  the  need  of  more  care  in  the  designing 
and  construction  of  them.     To  insure  the  best  results,  the  following 
features  should  have  attention. 

WOODEN    TANKS 

4  The  tightness  and  durability  in  the  wooden  tank  depends  chiefly 
upon  the  quality  of  the  lumber  and  the  details  of  its  construction. 
Selected  tank  stock  only  should  be  used  consisting  of  white  cedar, 
cypress,  white  pine,  Douglas  or  Washington  fir,  or  redwood,  and  the 
lumber  should  be  free  from  sap,  loose  or  unsound  knots,  worm-holes 


Presented  at  the  Annual  Meeting  1913,   of   THE  AMERICAN   SOCIETY   OF 
MECHANICAL  ENGINEERS. 

921 


922  ELEVATED    TANKS 

and  shakes,  and  be  thoroughly  air-dried.  Both  the  staves  and  bottom 
are  usually  made  up  of  2%-in.  stock  dressed  both  sides,  for  tanks  up 
to  16  ft.  in  diameter  and  16  ft.  deep;  for  larger  tanks  3-in.  stock  is 
used.  Planks  for  this  purpose  should  be  full  length  without  splices. 


FIG.  1     TYPICAL  DETACHED  TOWER  STRUCTURE  FOR  ELEVATED  TANK.     CAPAC- 
ITY 150,000  GAL.;  ELEVATION  242  FT.  TO  BOTTOM  OF  TANK 

5  The  strength  of  the  wooden  tank  depends  principally  upon  the  size 
and  spacing  of  the  iron  hoops.  The  importance  of  the  matter  of  the 
hooping  will  be  appreciated  when  it  is  realized  that  the  overstressing 
of  even  one  hoop  may  result  in  the  bursting  of  the  tank.  The  wooden 
tank  being  originally  merely  a  development  of  the  barrel  where  flat 
hoops  were  necessary  to  permit  of  tightening  by  driving  them  toward 
the  enlarged  middle,  it  was  natural  to  use  also  flat  hoops  for  the  tank 
and  the  tank  was  also  made  tapered  so  that  the  hoops  could  be  tight- 
ened by  driving,  although  later  they  were  tightened  principally  by 
hoop  lugs.  It  was  claimed  that  the  tapered  shape  had  also  the  advan- 


W.    O.    TEAGUE  923 

tage  of  preventing  the  hoops  from  dropping  down  over  the  tank,  if  it 
was  allowed  to  remain  empty  and  the  staves  to  shrink  from  drying. 

6  The  tapered  shape  of  tank  is  not  important,  however,  since  a 
tank  which  has  been  allowed  to  dry  up,  has  been  seriously  damaged 
thereby  and  cannot  be  made  tight  without  extensive  repairs,  some- 
times necessitating  the  rebuilding  of  it.  In  fact  most  tanks  are  now 
made  without  taper  and  the  hoops  are  found  to  remain  where  placed. 
The  tapered  tank  costs  somewhat  more  to  build  since  the  staves  must 
be  fitted  more  carefully  and  the  design  undoubtedly  would  have  been 
entirely  discarded  long  ago,  except  that  some  architects  and  pur- 
chasers believe  a  tapered  tank  presents  a  more  pleasing  appearance. 
The  amount  of  taper  is  so  small,  being  usually  1  in.  per  ft.,  thus  giv- 
ing a  batter  of  %  in.  per  ft.  to  each  side  of  tank,  that  its  absence  is 
hardly  noticeable  except  on  very  high  and  small  diameter  tanks.  The 
only  objection  to  the  tapered  tank,  however,  is  its  extra  cost. 


FIG.  2    APPEARANCE  OF  INSIDE  SURFACE  OF  FLAT  BAND  HOOP  THAT  BUSTED 
THROUGH  AND  FAILED  ON  WOODEN  TANK 

7  In  the  early  studies  of  this  subject  many  serious  failures  of 
tanks  were  traced  to  weakening  of  the  flat  hoops  by  their  rusting  at 
the  back  where  they  bore  against  the  staves,  due  to  moisture  from  rain 
being  retained  between  the  surfaces  of  the  hoop  and  staves.     Fig.  2 
shows  the  appearance  of  the  inside  face  of  a  flat  hoop  which  rusted 
through  and  allowed  a  tank  to  burst.     These  failures  were  largely 
unpreventable,  as  it  was  difficult  to  inspect  properly  the  condition  of 
the  hoops,  and  also  impossible  to  paint  them  while  the  tank  was  in 
service.     The  use  of  hoops  of  round  rod  without  welds  has  remedied 
this  trouble  as  their  surface  is  nearly  all  exposed  for  inspection  and 
painting,  and  also  they  are  not  so  subject  to  corrosion  since  the  ex- 
posed surface  of  a  round  rod  is  much  less  than  that  of  a  flat  bar  or 
band  of  the  same  cross  sectional  area. 

8  Eound  rod  hoops  are  now  being  used  exclusively  on  well  built 
sprinkler  tanks,  and  the  flat  hoops  of  a  large  percentage  of  previously 
built  tanks  have  been  replaced  with  them.    It  is,  of  course,  advisable 


924  ELEVATED    TANKS 

that  the  remaining  flat  hoops  also  be  replaced,  but  if  this  is  not  done, 
the  hoops  should  be  carefully  examined  every  few  years  to  note  their 
condition.  In  making  such  an  examination,  a  round  rod  hoop  should 
be  placed  on  each  side  of  one  of  the  lower  flat  ones,  within  easy  reach 
from  the  balcony;  the  flat  hoop  should  then  be  struck  smartly  with  a 
pointed  hammer  at  intervals  of  a  few  inches  all  around  to  detect  thin 
places,  or  else  the  hoop  should  be  removed  and  examined.  Examina- 
tion at  wider  intervals  is  not  sufficient  since  the  hoop  may  be  in  good 
condition  at  one  point  and  be  nearly  rusted  off  at  a  point  six  inches 
away.  If  this  lower  flat  hoop  is  found  to  be  corroded  materially,  all 
the  hoops  should  be  replaced  with  round  rod  ones,  or,  if  preferred,  the 
flat  ones  may  be  retained  and  round  rod  ones  placed  between  them. 


FIG.  3     PREFERABLE  DESIGN  FOR  END  LUGS  IN  MALLEABLE  IRON  FOR  BOUND 

EOD  HOOPS 

9  Another  point  of  weakness  in  the  flat  hoop  is  at  its  connection 
to  the  cast-iron  lugs  which  is  usually  made  by  riveting.     The  use  of 
round  rod  hoops?  however,  permits  of  a  satisfactory  connection  to  the 
lugs,  but  at  first  many  tank  failures  resulted  from  the  use  of  light  cast 
iron  lugs.     These  are  now  made  of  malleable  iron,  the  best  design 
being  shown  in  Fig.  3.    The  hoops  are  so  placed  on  the  tank  that  the 
lugs  do  not  come  in  a  vertical  line. 

10  Eound  rod  hoops  are  so  spaced  that  the  stress  will  not  exceed 
12,500  Ib.  per  sq.  in.  when  computed  from  area  at  the  root  of  the 
thread.    The  proper  spacing  can  readily  be  found  from  the  following 
formula : 

Safe  load  for  given  hoops  (Ib.) 
Spacmg  of  hoops  (m.)  ==  <>  6  x  diameter  (ft)  x  depth  (ft) 

The  depth  used  is  the  distance  from  overflow  to  point  where  hoop  is  to 
be  located.  The  top  hoop  is  placed  2  in.  from  the  top  of  the  staves  and 
the  spacing  between  hoops  should  in  no  case  exceed  21  in.  An  extra 
hoop  or  two  is  placed  at  the  croze  to  take  the  additional  strain  due  to 
the  swelling  of  the  bottom  planks. 


W.    O.    TEAGUE 


925 


11  The  tank  roof,  since  it  in  no  way  serves  to  retain  the  water,  has 
usually  been  nothing  more  than  a  make-shift  cover.  In  the  early  days 
a  single  flat  roof  was  used,  on  outdoor  tanks,  but  this  held  the  snow 
and  ice  and  required  strong  joist  supports  to  keep  it  tightly  in  place. 
The  snow  also  interfered  seriously  with  the  opening  of  the  hatch 
giving  access  to  the  interior  of  the  tank.  A  conical  roof  was  then 
built  over  the  flat  one  which  remedied  these  difficulties.  It  also 
greatly. increases  the  efficiency  of  the  roof  in  preventing  radiation  of 
heat  from  the  tank  water  in  winter  as  it  provides  a  dead  air  space 
between  it  and  the  flat  roof  in  addition  to  the  one  between  the  latter 
and  the  water,  thus  reducing  the  cost  of  heating  in  freezing  weather. 
The  conical  roof  also  gives  a  better  appearance  to  the  tank  top.  A 


FIG.  4    A  GOOD  DESIGN  OF  DOUBLE  EOOF  FOR  ELEVATED  TANK 

well  built  roof  is  shown  in  Fig.  4.    It  should  be  tightly  fitted  around 
the  tank  top  to  maintain  the  dead  air  spaces. 

12  The  roof  covering  which  was  most  generally  used  was  the 
wooden  shingle,  but  these  were  found  to  catch  fire  from  burning  em- 
bers which  spread  to  the  tank  staves,  weakening  them  so  that  the  tank 
burst.     Non-combustible  coverings,  such  as  galvanized  sheet  iron  and 
composition  roofings  are  now  used. 

13  Much  trouble  has  resulted  from  leakage  in  the  wooden  tank, 
because  it  has  not  been  firmly  supported.    The  wooden  tank  is  locally 
weak,  not  being  of  unit  construction,  and  the  lack  of  firm  support  has 
permitted  working  of  the  joints.     It  is  supported  only  from  the  bot- 
tom, none  of  the  weight  being  carried  by  the  staves.     Wooden  beams 
were  first  used  as  supporting  members,  and  these  were  placed  on  the 


926 


ELEVATED    TANKS 


roof  of  a  building  or  tower  as  a  grillage,  and  the  tank  bottom  set  on 
them.  In  time  the  wood  rotted  because  of  moisture  from  the  tank 
bottom,  permitting  the  tank  to  settle  and  causing  leakage;  there  was 
also  danger  of  collapse  of  the  tank  because  of  this  weakening  of  the 
joints.  The  use  of  steel  I-beams  as  grillage  members  as  shown  in  Fig. 
5  avoids  these  difficulties.  The  beams  should  not  be  spaced  over  18 
inches  clear  between  edges  of  flanges,  and  the  tank  bottom  is  placed 
directly  on  the  steel. 

STEEL   TANKS 

14    When  good  tank  lumber  began  to  get  scarce  and  to  increase 


FIG.  5    DETAIL  VIEW  OF  ARRANGEMENT  OF  STEEL  I-BEAM  GRILLAGE  FOR  SUP- 
PORT OF  TANK 

considerably  in  price,  boiler  and  iron  companies  turned  their  atten- 
tion to  the  manufacture  of  steel  tanks  and  towers,  especially  of  the 
larger  sizes.  In  the  design  and  construction  of  these  tanks,  the  manu- 
facturers have  drawn  on  their  extended  and  complete  experience  in 
boiler  and  bridge  work,  but  the  matter  of  supporting  the  tank  properly 
had  to  be  experimented  with  until  experience  with  tanks  in  ser- 
vice was  available.  The  simplest  form  of  steel  tank  is  the  flat  bot- 
tomed one  and  tanks  of  this  type  give  satisfactory  service,  provided 
the  bottom  is  supported  by  a  steel  grillage  as  in  the  case  of  the  wooden 
tank.  One  possible  source  of  trouble  is  from  corrosion  of  the  bottom, 
and  to  prevent  this  in  so  far  as  possible  the  bottom  plates  are  made 


W.    O.    TEAGUE 


927 


somewhat  thicker  than  is  necessary  for  strength  alone,  and  the  grillage 
I-beams  are  of  a  height  and  spacing  to  permit  of  inspection  and  paint- 
ing of  the  bottom.  When  the  tank  is  to  be  placed  on  a  concrete  tower, 
it  may  rest  directly  on  a  reinforced-concrete  slab  with  the  bottom 
thoroughly  grouted  in  place  with  neat  cement. 

15  The  preferred  form  of  a  tank  to  be  placed  on  a  steel  tower  is 
that  having  a  hemispherical  or  elliptical  bottom.  The  construction  in 
this  form  is  cheaper  than  for  the  flat  bottomed  tank  as  the  bottom  is 
self  supporting  and  a  steel  grillage  is  unnecessary.  The  entire  bottom 
is  also  accessible  for  inspection  and  painting,  and  corrosion  is  reduced 
to  a  minimum  since  the  plates  are  exposed  to  the  air. 


FIG.  6    DETAIL  OF  ATTACHMENT  OF  TANK  SHELL  TO  TOWER  POST  AND  CIRCULAR 

GIRDER  CONSTRUCTION 

16  Plates  for  use  in  steel  tanks  are  made  somewhat  thicker  than 
is  necessary  for  strength  in  order  to  make  them  durable  against  cor- 
rosion.   The  minimum  thickness  is  %  in.,  except  that  %-in.  plates  are 
used  for  roofs.    The  plates  composing  the  lowest  cylindrical  ring  are 
5/16  in.  thick  for  60,000-gal.  tanks  and  larger,  and  the  bottom  plates 
5/16  in.  thick  for  tanks  75,000  gal.  and  larger. 

17  One  of  the  weaknesses  of  steel  tank  construction  in  the  past 
has  been  poorly  designed  connections  of  the  tank  shell  to  the  posts  of 
the  supporting  tower.    When  the  posts  have  a  batter,  as  is  usually  the 


928  ELEVATED    TANKS 

case,  the  inward  thrust  due  to  the  horizontal  component  of  the  weight 
is  provided  for  by  a  circular  girder  consisting  of  i/i-in.  plate  24  in. 
wide,  attached  to  the  lowest  cylindrical  ring  by  an  angle  and  stiffened 
by  angles  or  a  channel  at  the  outside  edge,  as  shown  in  Fig.  6.  The 
posts  also  connect  to  the  tank  shell  at  this  point  and  the  design  is  such 
that  the  load  will  be  transferred  from  the  shell  to  the  center  line  of 
the  posts  so  as  to  avoid  eccentric  loading.  A  number  of  tanks  built 
without  circular  girders  have  failed  by  the  posts  crushing  in  the  tank 
plates.  Others  with  the  girder,  but  having  eccentrically  loaded  con- 
nections to  the  posts,  have  failed  by  bending  of  the  upper  posts. 

18  As   the  hydrostatic   pressure   on   the   tanks   is   comparatively 
small,  it  is  not  necessary  to  provide  standard  riveting  for  the  thickness 
of  plates  used.    The  joints  of  the  plates  should  be  riveted  so  that  the 
unit  stresses  on  the  net  section  of  the  plates  and  rivets  will  not  exceed 
7500  Ib.  for  shearing  and  20,000  Ib.  for  bearing.    The  horizontal  joints 
are  single  lap  riveted,  except  between  the  lowest  cylindrical  ring  and 
the  bottom,  which  are  double  lap  riveted.     The  vertical  joints  also 
are  single  lap  riveted  except  those  in  the  lowest  cylindrical  ring,  which 
are  double  lap  riveted.     The  rivets  are  entered  from  the  outside  and 
driven  from  the  inside  and  the  inside  seams  calked.    One  of  the  strong 
features  of  the  steel  tank  is  that  when  once  made  tight,  it  gives  prac- 
tically no  trouble  from  leakage. 

TOWERS   FOR   ELEVATED    TANKS 

19  Towers  to  support  wooden  tanks  were  originally  built  of  .wood. 
While  the  tanks  were  small  in  size,  say  up  to  20,000  gal.  capacity,  and 
elevated  to  a  comparatively  moderate  height,  this  construction  proved 
fairly  satisfactory.    With  the  increases  in  size  of  plant  buildings  and 
extensions  of  them,  considerably  larger  tanks  and  higher  towers  were 
required,  and  the  builders,  realizing  the  inadequacy  of  wooden  con- 
struction under  these  conditions,  began  to  make  towers  of  steel.     One 
manufacturer  built  towers  of  iron  pipe  construction  having  from  four 
to  twelve  posts  and  the  members  connected  by  cast  iron  fittings,  but  it 
was  practically  impossible  to  provide  resistance  against  uplift  due  to 
wind  pressure,  and  with  the  tank  empty  the  structure  was  in  great 
danger  of  overturning.     The  inside  of  the  pipe  was  subject  to  corro- 
sion and  as  its  condition  could  not  be  inspected  or  the  surface  painted, 
the  metal  might  be  greatly  weakened  without  its  showing  on  the  out- 
side.   These  towers  were  sold  largely  in  a  knocked-down  condition  by 
mail  order  and  erected  by  the  purchaser  who  of  course  could  not  be 
expected  to  have  expert  knowledge  as  to  their  construction.     Ob- 


W.    O.    TEAGUE  929 

* 

viously,  these  towers  should  not  be  depended  on  for  such  an  important 
use,  and  it  is  advisable  to  replace  those  already  built  with  well-de- 
signed structural  steel  towers  to  forestall  failure. 

20  The  wooden  tank  manufacturers'  shops  were  originally  fitted 
only  with  woodworking  machinery,  so  that  it  became  necessary  for 
them  to  prepare  for  the  fabrication  of  steel  work.  The  managements 
not  being  experienced  in  structural  steel  designing,  naturally  selected 
the  simplest  design  possible  for  the  towers  The  posts  and  girts  con- 
sisted usually  of  two  angle  irons,  placed  apex  to  apex  and  strapped 
together  at  intervals  of  several  feet  by  tie-plates  shop  riveted  to  the 
angles.  The  column  sections  were  spliced  by  angles  which  were  shop- 
riveted  at  one  end  to  the  post ;  the  other  end  was  field-bolted  in  erect- 
ing the  tower,  as  this  was  the  simplest  form  of  connection  and  the 
easiest  one  to  make.  Furthermore,  it  had  the  advantage  that  the 
bolting  could  be  done  by  the  regular  erecters  which  made  it  unneces- 
sary to  have  first-class  mechanics  in  the  erecting  gangs  and  to  carry 
special  tools.  This,  however,  was  not  good  construction  and  the  man- 
ufacturers are  now  field-riveting  these  connections. 

2*1  The  struts  were  at  first  connected  directly  to  the  posts  by  bolts. 
This  construction  is  objectionable  because  the  bolts  are  apt  to  work 
loose  and  it  does  not  brace  the  parts.  The  construction  now  used  is 
that  of  gusset  plates  riveted  to  the  posts  and  girts.  The  wind  rods 
were  also  connected  directly  to  the  posts  at  the  girts.  The  bolt  holes, 
as  originally  inserted  through  the  post  angles,  weakened  the  posts 
since  they  reduced  the  net  section.  The  rods  are  now  connected  to 
the  gusset  plates.  The  arrangement  of  these  parts  is  shown  in  Fig. 
5.  The  diameter  of  bolt  and  thickness  of  plate  are  proportioned  to 
provide  proper  bearing  strength. 

22  The  posts  and  girts  of  steel  towers  erected  to  support  steel 
tanks,  and  to  some  extent  wood  tanks,  are  now  largely  made  of  chan- 
nels latticed  on  both  sides  or  having  a  plate  on  one  side.    Other  shapes 
such  as  the  Bethlehem  H-beam  and  two  channels  with  an  I-beam  be- 
tween to  form  an  H-section  are  also  used  to  some  extent. 

23  Competition  in  the  manufacture  of  these  structures  has  resulted 
in  the  use  of  too  high  unit  stresses  and  as  a  result  the  posts,  figured  on 
a  conservative  basis  as  represented  in  case  of  other  structural  work 
such  as  bridges,  had  a  factor  of  safety  of  less  than  4  and  sometimes 
as  low  as  2%.     Failure  has  resulted,  an  example  of  which  is  shown 
in  Fig.  7,  a  view  of  a  large  structure  after  a  collapse.    To  obtain  safe 
towers  it  became   necessary,   therefore,   to   set  maximum   allowable 
stresses.     The  loading  of  the  structure  consists  of  the  weight  of  the 


9.30 


ELEVATED    TANKS 


W.  O.  TEAGUE 


931 


structural  and  ornamental  steel  work,  platforms,  roof,  piping,  etc. 
The  live  load  consists  of  the  weight  of  the  total  volume  of  water ;  the 
movable  load  on  the  platform  is  assumed  to  be  30  Ib.  per  sq.  ft.  and 
the  wind  load.  The  wind  pressure  is  assumed  at  30  Ib.  per  sq.  ft.  and 
that  on  the  tank  is  this  pressure  times  6/10  the  projected  area  of 
tank  and  roof,  and  in  the  case  of  steel  tanks,  the  curved  bottom.  The 
total  wind  pressure  on  the  posts,  struts,  wind  rods,  ladders  and  riser 
boxing  is  assumed  at  200  Ib.  per  linear  ft.  of  height  of  tower. 


FIG.  8     UNUSUAL  CASE  OF  LOADING  OF  LARGE  STEEL  TOWER  STRUCTURE  BY 
ICE;  60,000-GAL.  TANK  ON  A  79-FT.  TOWER,  UNINJURED  AFTER  THAW 

24  An  unusual  loading  of  a  steel  tower  structure  by  ice  is  shown 
in  Fig.  8.     The  tank  is  60,000  gal.  on  79-ft.  tower  and  is  located  at 
Richfield,  Idaho.     The  ice  coating  was  formed  from  repeated  over- 
flowing of  the  tank  during  cold  weather.    When  warm  weather  melted 
the  ice,  the  structure  was  found  to  be  uninjured.     This  experience 
illustrates -the  abuse  a  well-built  structure  will  withstand. 

25  All  parts  of  the  structure  are  proportioned  so  that  the  sum 
of  the  dead  and  live  loads  shall  not  cause  the  stresses  to  exceed  those 


932 


ELEVATED    TANKS 


FIG.  9     TYPICAL  CONSTRUCTION  OF  FOOTING  FOR  ANGLE  IRON  COLUMN 


FIG.  10    TYPICAL  CONSTRUCTION  OF  FOOTING  FOR  CHANNEL  COLUMN 


W.    O.    TEAGUE  933 

allowable.  The  principal  stresses  in  such  a  tower  structure  are  axial 
compression  on  gross  section  of  columns  and  struts,  axial  tension  on 
net  section  of  wind  rods,  bending  on  extreme  fibers  or  net  section  of 
rolled  shapes,  built  sections  and  struts,  and  shearing  of  rivets.  The 
axial  compression  on  gross  section  of  columns  and  struts  is  determined 

from  the  following  expression :    17, 100  --57—  ,  where  L  is  the 

R 

unsupported  length  of  the  member  from  center  to  center  of 
connections  in  inches,  and  R  the  least  radius  of  gyration  in 

inches;  the  ratio   -  -    should  not  exceed  125  for  columns  and   150 

for  struts  and  minor  members  and  the  maximum  compression  allow- 
able as  thus  determined  is  12,000  Ib.  per  sq.  in.  The  axial  tension  on 
net  section  of  wind  rods  must  not  exceed  12,500  Ib.  per  sq.  in.;  the 
bending  on  extreme  fibers  or  net  section  of  rolled  shapes,  built  sec- 
tions and  struts  16,000  Ib.  per  sq.  in.,  and  the  shearing  for  shop  driven 
rivets,  10,000  Ib.  per  sq.  in.  and  field  driven  rivets  7,500  Ib.  per  sq.  in. 

26  The  lower  ends  of  the  posts  have  not  been  as  carefully  designed 
as  their  importance  requires.     Frequently,  in  angle  iron  towers  par- 
ticularly, no  special  attempt  has  been  made  to  properly  distribute 
the  load  to  the  base  plate  attached  to  the  post  footing.     Cast-iron 
plates  were  first  used  and  the  concentrated  loading  caused  these  to 
crack,  resulting  in  collapse  or  in  throwing  the  structure  dangerously 
out  of  plumb  with  possibility  of  failure  of  the  foundation  under  this 
post.    The  present 'use  of  steel  plates  has  improved  conditions,  but  the 
design  must  be  such  as  to  distribute  the  load  to  them  as  shown  in 
Figs.  9  and  10,  which  are  designs  that  are  being  used  quite  generally. 

27  In  anchoring  the  columns  to  the  foundations,  the  diameter  of 
the  bolt  at  root  of  thread  should  be  such  as  to  withstand  the  maximum 
uplift  due  to  the  wind  with  tank  empty,  and  to  resist  the  shearing 
force  at  base  plate.     The  bolts  should  be  made  from  round  wrought 
iron  or  mild  steel  rods  without  upsets. 

FOUNDATIONS  AND   SUPPORTS 

%8  The  foundation  piers  to  support  steel  towers  are  usually  made 
of  concrete,  consisting  of  one  part  portland  cement,  three  parts  clean 
sand  and  five  parts  broken  stone.  They  are  usually  pyramidical  in 
shape  and  proportioned  to  suit  soil  conditions.  The  allowable  bearing 
pressures  on  soil  will  range  from  1  to  5  tons  per  sq.  ft.,  depending 
on  the  quality  of  the  soil.  Where  the  soil  is  moist  or  rather  loose,  a 


934  ELEVATED    TANKS 

girt  should  be  provided  at  the  base  of  the  tower  to  prevent  spreading 
of  the  posts.  The  allowable  bearing  pressures  for  footings  should  not 
exceed  400  Ib.  per  sq.  in.  for  portland  cement  concrete  and  200  Ib.  per 
sq.  in.  for  ordinary  brick  work  with  portland  cement  mortar,  except 
when  the  tank  is  to  be  rested  on  the  building  walls,  when  the  bearing 
plate  should  be  figured  on  the  basis  of  125  Ib.  per  sq.  in. 

29  The  weight  of  the  foundation  pier  when  buried  at  least  two- 
thirds  of  its  height  should  be  equivalent  to  the  calculated  net  uplift 
due  to  wind  pressure  with  the  tank  empty,  that  will  be  transmitted  to 
it;  otherwise  it  should  be  one  and  one-half  times  that  amount. 

30  Where  the  tank  structure  is  above  a  building,  and  the  building 
walls  are  depended  upon  to  act  as  supports,  great  care  should  be  taken 
to  determine  that  the  construction  is  safe  against  collapse.    In  many 
cases,  tanks  are  supported  by  building  walls  not  originally  built  to 
carry  them,  but  where  a  sprinkler  system  was  later  installed  it  was 
considered  more  convenient  and  cheaper  to  use  the  walls  than  to 
erect  a  detached  tower  for  the  tank.     This  has  frequently  been  done 
without  making  a  thorough  inspection  first  of  the  condition  of  the 
walls,  and,   largely  through  ignorance,   the  necessary  care  was  not 
taken  to  distribute  the  load.     Many  failures  have  consequently  re- 
sulted and  there  are  no  doubt  numerous  cases  of  this  kind  where  the 
tanks  are  apt  to  fall  at  any  time.    A  serious  cracking  of  the  walls  in 
such  an  installation  is  shown  in  Fig.  11. 

31  Inspection  should  be  made  of  the  quality  and  condition  of  the 
brick  and  mortar  or  other  material  used  in  the  construction.     The 
wall  foundations  should  be  examined  as  to  construction  and  bearing 
on  soil  or  rock.     The  condition  of  the  bond  between  abutting  walls 
should  be  noted  and  a  general  inspection  made  for  sizable  cracks  in 
the  walls.    The  thickness  of  walls  and  size  and  spacing  of  window  and 
door  openings  should  be  measured  and  calculations  then  made  to  de- 
termine if  the  load  of  tank,  water  and  trestle  can  be  safely  distributed 
over  the  walls.    All  unnecessary  openings  should  be  bricked  or  other- 
wise solidly  filled  in,  and  it  may  be  necessary  to  sacrifice  some  open- 
ings to  obtain  the  required  strength.    When  the  walls  cannot  be  al- 
tered to  support  the  load,  the  additional  support  required  can  be 
obtained  by  carrying  steel  beams  down  inside  the  walls  to  a  solid  foun- 
dation, provided  these  do  not  interfere  with  the  occupation  of  or  the 
processes  carried  on  in  the  building.     Otherwise  it  will  be  necessary 
to  provide  a  separate  steel  tower. 


W.    O.    TEAGUE 


935 


32  The  proper  strength  of  foundations  is  especially  important 
because  of  the  greater  probability  of  loss  of  life  from  the  falling  of  a 
tank  from  above  a  building  as  compared  with  the  falling  of  a  tank  on 
a  detached  tower.  The  monetary  loss  is  liable,  of  course,  to  be  also 
much  greater,  as  the  water  will  undoubtedly  wreck  the  building  and 
cause  heavy  water  damage.  The  building  departments  of  cities  en- 
deavor to  obtain  proper  construction,  but  unfortunately  they  do  not 


FIG.  11 


VIEW  OF  SUPPORTING  WALL  THAT  HAS  CRACKED  UNDER  WEIGHT  OP 
TANK 


always  succeed.  The  possibility  of  trouble  is  increased  because  of  the 
divided  responsibility  of  the  tank  builder  and  the  architect.  The 
former  seldom  concerns  himself  as  to  the  strength  of  the  supporting 


936 


ELEVATED    TANKS 


FIG.  12    EXAMPLE  OF  PROPER  DESIGN  OF  EXPANSION  JOINT  FOR  WOODEN  TANK 


FIG.  13    EXAMPLE  OF  PROPER  DESIGN  OF  EXPANSION  JOINT  FOR  STEEL  TANK 


W.    O.    TEAGUE  937 

walls,  assuming  that  the  latter  has  given  the  matter  proper  attention, 
so  he  goes  ahead  and  erects  the  tank  according  to  contract. 

GENERAL  FEATURES 

33  Tank  fittings  should  receive  careful  attention  to  insure  the 
reliability  of  the  equipment.     The  discharge  or  riser  pipe  is  more 
serviceable   if  made  up  of   cast  or  wrought-iron   pipe,   flanged  or 
coupled,  than  one  made  up  of  bell  and  spigot  pipe,  since  the  latter  is 
apt  to  leak  at  the  leaded  connections,  necessitating  removal  of  the 
frost-proof  boxing  to  permit  of  repairs.     A  tank  and  tower  is  con- 
stantly swaying  from  side  to  side  and  this  tends  to  loosen  up  leaded 
joints.    Furthermore,  the  increased  rigidity  of  the  flanged  and  coupled 
pipe  permits  the  use  of  a  minimum  number  of  tie  rods.     There  are 
usually  four  rods  connected,  one  to  each  post,  at  girt  connections. 

34  The  connection  of  the  discharge  or  riser  pipe  to  wooden  tanks 
has  usually  been  made  by  extending  the  pipe  through  ordinary  cast- 
iron  slip  flanges  bolted  to  the  tank  bottom  on  each  side  of  the  opening. 
The  hole  in  the  planks  was  cut  larger  than  the  size  of  the  pipe  to  form 
a  packing  space  which  was  filled  when  parts  were  first  assembled.    A 
better  construction  was  used  for  steel  tanks  having  a  stuffing  box  and 
gland.    Both  types  of  joints  were  found  to  be  unserviceable,  however, 
the  former  because  the  joint  could  not  be  tightened  when  leakage  oc- 
curred, and  the  latter  principally  because  the  iron  to  iron  parts  rusted 
together,  which  resulted  in  the  breaking  of  some  pipe  fitting  and  the 
emptying  of  the  tank.     Examples  of  properly  designed  expansion 
joints  forming  tank  connections  for  wooden  and  steel  tanks  are  shown 
in  Figs.  12  and  13,  respectively.     These  have  a  bronze  gland  and 
ample  clearance  between  the  iron  parts  to  prevent  binding  by  corro- 
sion.   The  packing  space  is  large  and  the  joint  is  extended  within  the 
tank  bottom  to  form  a  settling  basin,  to  prevent  sediment  getting  into 
the  yard  pipe  and  clogging  the  sprinklers  at  time  of  fire. 

35  A  tightly  constructed  frost  boxing  should  be  placed  around 
the  discharge  or  riser  pipe,  and  arrangements  made  for  keeping  the 
water  heated  by  a  hot  water  heater  or  a  steam  coil  in  the  bottom  of  the 
tank.    Designs  of  three-ply,  two  air-space  boxings  are  shown  in  Figs. 
14  and  15. 

36  A  tank  level  indicator  or  telltale  is  necessary  to  give  a  positive 
indication  that  the  tank  is  full  at  all  times.    After  many  serious  fires 
it  has  been  learned  that  the  tank  had  been  partially  or  wholly  empty 
at  the  start  of  the  fire,  and  the  lack  of  water  had  handicapped  the  fire 
protection  devices.     Tanks  may  be  left  empty  due  to  neglect,  but 


938 


ELEVATED    TANKS 


usually  so  because  of  false  indication  of  the  telltale.  The  most  used 
type  of  device  for  this  purpose  is  the  float  in  the  tank  water,  operating 
a  target  sliding  on  a  scale  fixed  to  the  outside  of  tank.  Obviously, 


FIG.  14    DESIGN  OF  EFFICIENT  FROST-PROOF  SQUARE  BOXING  FOR  ENCLOSURE 
OF  EISER  PIPE  TO  TANK  CONNECTION 


FIG.  15 


DESIGN  OF  EFFICIENT  FROST-PROOF  BOUND  BOXING  FOR  ENCLOSURE 
OF  EISER  PIPE  TO  TANK  CONNECTION 


these  are  subject  to  sticking  due  to  their  mechanical  construction  and 
exposure  to  snow  and  ice  in  freezing  weather.  The  ordinary  pressure 
gage  has  been  largely  used  but  cannot  be  positively  depended  on,  since 
it  is  seldom,  if  ever,  tested  and  the  parts  stick,  causing  false  readings. 
There  are  several  types  of  electrical  telltales  operated  by  a  float,  but 
these  are  complicated  and  easily  gotten  out  of  adjustment.  Attention 
is  also  necessary  to  maintain  the  electrical  current. 


W.    O.    TEAGUE 


939 


37  The  most  reliable  telltale  is  undoubtedly  the  mercury  gage,  an 
adaptation  of  which  for  this  purpose  is  shown  in  Fig.  16.  This  gage 
was  developed  by  the  laboratories  of  the  Associated  Factory  Mutual 
Fire  Insurance  Companies.  It  should  be  placed  indoors  where  it  will 
be  observed  and  cared  for.  The  mercury  pot  is  then  piped  to  the 


The  qauqe  board 
shown  is  fora  tank 
20 'deep.  Similar 
boards  to  be  pro- 
vided according  to 
depth  of  tank. 


Connection  to  tank 
riser  on  tank  side 
of  check  valve.  Pipe 
to  be  as  short  as 
possible  and  with- 
out air  pockets  to 
avoid  -false  reaotinoj. 


FIG.  16  DETAILS  OF  MERCURY  GAGE  FOR  INDICATING  WATER  LEVEL  IN  TANK 
riser  pipe  on  the  tank  side  of  the  check  valve,  and  the  gage  board  ad- 
justed after  filling  the  mercury  pot.  The  gage  is  readily  tested  by 
opening  the  pet  cock  on  the  water  pipe.  If  water  continues  to  flow 
under  constant  pressure,  the  apparatus  is  in  operative  condition ; 
otherwise,  the  pipe  is  clogged  or  there  is  a  valve  closed. 


940  ELEVATED    TANKS 

38  The  painting  of  steel  tanks  and  towers  and  of  the  iron  hoops 
of  wooden  tanks  is  very  important  to  prevent  corrosion.     Steel  plates 
and  shapes  should  be  given  the  usual  priming  coat  at  the  shop.    The 
surface  of  the  metal  should  be  thoroughly  cleaned  of  mill  scale,  rust 
and  grease  and  be  perfectly  dry  before  applying  the  paint.     A  good 
paint  for  the  first  coat  is  made  by  mixing  20  Ib.  of  red  lead  and  10  Ib. 
of  zinc  oxide  with  3  qt.  of  boiled  linseed  oil,  the  red  lead  and  zinc 
oxide  being  ground  in.    This  amount  of  paint  will  cover  about  50  sq. 
yd.  of  surface.    A  second  coat  should  be  applied  after  structure  has 
been  erected.    For  this  a  more  durable  oil  or  asphaltum  paint  should 
be  used. 

39  The  inside  of  a  steel  tank  should  be  repainted,  usually  every 
two  years,  or  oftener,  if  the  paint  shows  signs  of  peeling  or  wear.    The 
outside  of  the  tank  and  the  tower  should  be  repainted  at  about  five- 
year  intervals.    The  surface  should  be  carefully  cleaned  either  by  sand 
blast  or  by  steel  brushes  or  scrapers. 

40  The  iron  hoops  of  wooden  tanks  should  receive  a  priming  coat 
as  for  structural  steel  and  a  second  coat  after  assembly.    They  should 
be  repainted  when  necessary.     The  advisability  of  painting  wooden 
tanks  exposed  to  the  weather  is  an  open  question  although  a  large 
percentage  of  the  tanks  are  painted.    There  is  no  doubt  but  that  paint 
protects  wood  under  ordinary  conditions,  but  the  objection  raised  to 
its  use  on  tanks  is  on  the  ground  that  the  tank  water  percolates 
through  the  staves  and  is  prevented  from  evaporating  as  it  is  held 
under  the  paint  and  this  is  likely  to  set  up  dry  rot  in  the  wood.    It  is 
well  known,  however,  that  dry  rot  does  not  occur  when  wood  is  com- 
pletely immersed  but  rather  when  it  is  in  a  moist  condition  in  the 
presence  of  some  heat.    This  objection  is  not  considered  well-founded 
and  as  a  rule  the  tanks  are  undoubtedly  preserved  by  painting. 

41  The  life  of  properly  constructed  equipments  depends  largely 
upon  the  care  and  attention  given  to  them  by  property  owners.    The 
tanks  should  be  used  only  for  fire  protection.     The  practice  of  using 
a  foot  or  so  of  water  from  the  top  of  the  tank  for  mill  purposes  is  ob- 
jectionable as  the  tank  collects  a  larger  amount  of  sediment  from  the 
water  which  is  constantly  being  supplied  than  it  does  when  used  for 
fire  service  only.     This  sediment  is  likely  to  settle  in  the  sprinkler 
pipes  and  either  clog  them  completely,  or,  if  the  sprinklers  are  open, 
seriously  interfere  with  their  discharge.    If  water  is  drawn  from  the 
bottom  for  mill  purposes  the  tank  may  be  empty  when  needed  for  fire 
service.     Furthermore,  the  fluctuation  in  water  level  is  apt  to  result 
in  shrinkage  of  the  upper  ends  of  the  staves  of  wooden  tanks,  causing 


W.    O.    TEAGUE  941 

leakage  and  hastening  corrosion  in  the  steel  tank  by  the  repeated 
wetting  and  exposure  of  the  sides  to  the  air. 

42  Manufacturers  in  general  have  awakened  to  the  advisability  of 
following  the  best  practice  in  the  designing  and  construction  of  tanks 
and  towers  as  represented  by  the  foregoing,  and  are  now  making 
structures  which  are  serviceable  and  safe. 

DISCUSSION 

J.  W.  KETLEK1  (written).  Improperly  designed  supports  for  tank 
structures  on  buildings  and  the  sub-foundations  are  likely  to  endanger 
life  and  property.  As  an  engineer  making  a  specialty  of  this  work  I 
come  in  contact  with  faulty  designs,  principally  in  the  building  itself. 
The  fault  does  not  lie  entirely  with  the  structural  engineer,  but  in  a 
great  many  cases  with  the  architect.  I  would  suggest  stringent  rules 
governing  the  installation  of  these  outfits,  especially  the  thorough 
examination  of  the  building  by  a  competent  engineer  or  architect 
familiar  with  this  class  of  work.  I  would  also  suggest,  and  would  co- 
operate to  further  the  acceptance  of  one  uniform  set  of  specifications 
governing  the  engineering  manufacture  and  erection  of  towers  and 
tanks,  both  on  the  ground  and  on  buildings,  by  all  insurance  com- 
panies, and  so  far  as  possible  by  individuals,  corporations  or  city  build- 
ing departments. 

B.  A.  FREEMAN2  (written).  Lack  of  uniformity  in  the  design  of 
tanks  and  towers  at  present  is  well  known  to  those  interested  in  that 
line  of  work.  Besides  the  cause  suggested,  close  competition,  the  lack 
of  ability  on  the  part  of  most  purchasers  to  discern  the  merits  and 
demerits  of  designs  submitted  helps  not  a  little  towards  that  end. 
There  is  little  novel  or  unusual  in  the  construction  of  these  structures. 
All  of  the  problems  connected  with  them  have  been  solved  before  in 
connection  with  other  engineering  works.  Now  that  elevated  tanks 
and  towers  have  come  into  general  use  for  fire  protection  purposes, 
it  is  advisable  both  to  protect  the  purchaser  and  the  bidder  who  wishes 
to  erect  a  good  structure,  that  a  specification  be  forthcoming  which 
shall  place  all  competitors  on  the  same  basis.  A  worthy  attempt  in 
that  direction  has  been  recently  made  by  the  engineering  department 
of  the  Associated  Factory  Mutual  Fire  Insurance  Company  of  Boston, 

1  Chief  Engineer,  Wondnagel  &  Co.,  Chicago,  III. 

2  Engineer,  The  Rusling  Company,  New  York. 


942  ELEVATED    TANKS 

and  intelligent  inspections  in  connection  with  such  a  specification 
should  produce  very  good  results. 

BRYAN  BLACKBURN1  (written).  Too  much  credit  can  not  be 
given  to  Mr.  Teague  and  his  associates  for  the  splendid  service 
rendered  along  the  line  of  tank  betterment.  The  specifications  issued 
by  his  office,  if  honestly  carried  out,  will  afford  a  high-class  structure 
that  is  simple  in  design,  economical  in  construction  and  very  efficient 
in  service.  I  have  designed  a  vast  number  of  elevated  tanks  for  fire 
protection,  and  I  can  say  without  fear  of  contradiction  that  the  tanks 
built  under  the  requirements  of  Mr.  Teague's  office  are  beyond  criti- 
cism. 

I  differ  with  Mr.  Teague,  however,  in  that  it  is  allowable  to  single- 
rivet  the  vertical  searns  above  the  first  course.  As  pointed  out  in  my 
article  on  this  subject  in  The  Engineering  Magazine,2  the  vertical 
seams  should  be  double  riveted,  not  so  much  for  strength  of  joint,  as 
to  prevent  the  breaking  of  the  calking  edge  by  breathing  tendency  of 
shell  due  to  change  in  water  level ;  also  it  is  my  opinion,  based  on 
experience,  that  the  riveting  should  be  closer  than  is  theoretically  re- 
quired for  efficiency  of  joint,  in  order  to  insure  that  the  plates  be 
well  drawn  together  under  .field  riveting.  The  joints  in  the  main 
column  at  strut  points  should  be  milled  to  insure  full  bearing. 

The  formulae  and  stresses  set  forth  in  the  paper  for  main  members 
are  correct  and  ample,  but  I  would  suggest  that,  while  the  struts 
should  be  of  such  section  as  to  provide  for  all  live  and  dead  loads, 
and  that  the  depth  of  strut  should  be  such  that  the  unit  stress  due  to 
weight  of  member  should  not  exceed  4000  Ib.  per  sq.  in.,  still  my 
experience  indicates  that  more  often  the  sizes  of  these  struts  are  fixed 
by  the  requirement  that  no  strut  shall  exceed  150  radii  of  gyration  in 
length. 

In  the  using  of  the  Bethlehem  H  column  for  main  columns,  as 
suggested  by  Mr.  Teague,  care  should  be  exercised  to  see  that  the 
column  lengths  do  not  exceed  125  radii  of  gyration.  The  standard 
practice  in  these  elevated  tanks  allows  very  long  column  lengths  in  the 
latticed  channels  columns  and,  this  has  led  some  inexperienced  de- 
signers to  employ  H  shapes  in  too  long  lengths,  with  results  that  are 
not  pleasing,  and  in  several  cases  that  have  come  under  my  observa- 
tion, partial  failures  have  resulted,  not  from  any  inherent  defect  of 
the  H  sections  but  from  misuse. 

1  Assistant  Engineer,  R.  &  D.  Cole  Mfg.  Co.,  Newnan,  Ga. 

2  Elevated  Tanks  for  Fire-Protective  Service,  p.  385. 


DISCUSSION  943 

.Stress  must  be  laid  on  the  fact  that  the  so-called  balcony  used  on 
hemispherical-bottom  steel  tanks  is  not  an  ornament  but  a  horizontal 
girder  subjected  to  large  loads  due  to  the  horizontal  component  of  the 
stress  in  the  column. 

A.  H.  HAYES  (written).  It  is  generally  conceded  that  in  all 
structures  on  which  the  lives  of  men,  or  the  safety  of  property  from 
destruction  are  dependent,  too  much  care  can  not  be  taken  in  design 
and  construction;  this  is  the  business  of  the  designing  engineer. 
It  is  also  his  duty  in  this  day  of  efficiency,  so  to  plan  his  structure 
that  he  may  use  no  more  material  than  is  necessary  to  take  care  of  the 
maximum  loading  which  may  occur,  with,  of  course,  the  proper  factor 
of  safety. 

In  the  latter  part  of  the  section  on  towers,  the  author  states  that 
"the  total  wind  pressure  on  the  posts,  struts,  wind  rods,  ladders  and 
riser  boxing  is  assumed  at  200  Ib.  per  lineal  ft.  of  height  of  tower." 
This  is  taken  to  mean  that  for  all  towers  carrying  tanks,  whether  of 
10,  20,  or  100,000  gal.  capacity,  the  wind  pressure  must  be  assumed 
to  be  the  same.  This  appears  inconsistent,  inasmuch  as  the  size  and 
shape  of  the  members  will  vary  with  the  style  of  construction,  and  the 
loads  they  are  to  carry. 

The  writer  has,  in  several  years'  experience,  designed  many  towers 
to  carry  the  smaller  tanks  on  which  the  wind  pressure,  taken  at  30 
Ib.  per  sq.  ft.  of  flat  surface,  did  not  reach  150  Ib.  per  vertical  ft. ;  also 
others  of  larger  capacity,  where  the  wind  pressure  greatly  exceeded 
200  Ib.  per  vertical  ft.  This  is  a  small  consideration  when  designing 
low  towers,  but  with  comparatively  high  towers  where  the  wind 
stresses  at  the  base  of  the  tower  equal  or  exceed  those  caused  by  the 
weight  of  tank,  tower  and  water,  the  difference  amounts  in  some 
instances  to  15  per  cent.  Therefore,  a  strict  economy  of  material  is 
not  possible. 

I  wish  to  present  for  consideration  another  point  along  this  line 
not  brought  out  in  the  author's  paper,  but  which  is  embodied  in  the 
Specifications  for  Gravity  Tanks  and  Towers,  recently  published  by 
the  Associated  Factory  Mutual  Fire  Insurance  Companies,  with  which 
specifications,  it  appears,  the  author  is  largely  to  be  credited;  that  is 
the  practice  of  assuming  that  the  wind  pressure  on  the  tower  is  the 
same  when  acting  in  the  direction  of  the  diagonal  of  the  tower  as 
when  acting  in  the  plane  of  the  bents.  This  is  not  correct  when  the 
posts  are  made  up,  as  with  many  of  the  smaller  towers,  of  two  angles 


944 


ELEVATED    TANKS 


placed  corner  to  corner  forming  a  star  section  as  illustrated  in  Fig.  4. 
Here  the  wind  surface,  when  the  wind  is  acting  in  the  direction  of 

Of 

the  diagonal  of  the  tower  is  Therefore,  the  maximum  com- 

y* 

pression  stress  in  the  post  on  the  leeward  side  of  the  tower,  due  to 
wind  on  the  posts,  is  exactly  the  same  as  when  the  wind  is  acting  in 
the  plane  of  the  bents.  The  pressure  in  the  struts,  wind  rods  and 
riser  boxing  is  the  same  whether  the  wind  acts  in  one  direction  or 
another,  and  the  practice  of  increasing  these  stresses  by  the  square 


r 


FIG.  17    SURFACE  EXPOSED  TO  WIND  IN  POST  FORMED  OF  Two  ANGLES 

root  of  2  is  correct.  But  in  some  towers  the  wind  pressure  on  the 
posts  is  the  greater  part  of  the  total.  Take  a  case  where  50  per  cent 
of  the  total  wind  pressure  is  on  the  posts;  then  instead  of  increasing 
the  total  wind  stresses  by  the  square  root  of  2,  only  50  per  cent  should 
be  thus  increased. 

Taking  into  consideration  the  fact  that  an  assumption  of  200  Ib. 
per  vertical  foot  in  many  cases  raises  the  total  actual  stresses  in  the 
posts  15  per  cent,  and  that  the  latter  assumption  increases  them  an- 
other 10  per  cent,  it  appears  that  the  author  has  gone  even  beyond 
the  limits  of  conservatism,  and  in  order  to  meet  these  requirements 
the  manufacturer  is  compelled  to  use  considerably  more  material  than 
is  needed.  This  matter  should  be  left  as  an  incentive  to  each  indi- 
vidual engineer  to  design  his  structure  so  as  to  present  the  least 
possible  wind  surface,  and  thus  produce  an  economical  design. 


ALBERT  BLAUVELT  (written).    I  take  issue  with  the  statement  rec- 
ommending a  water  level  indicator  to  be  placed  indoors.     Such  an 


DISCUSSION  945 

indicator  is  limited  to  showing  the  water  level  in  the  tank  and  may 
not  do  that  because  the  operator  can  not  be  relied  upon  to  use  the 
test  cock  alluded  to,  to  prove  that  the  connections  are  clear.  As  a 
matter  of  field  service,  it  is  preferable  to  use  a  sight  overflow  pipe 
placed  vertically  inside  the  tank,  with  the  upper  end  at  the  desired 
full  elevation  of  water  and  the  lower  end  extending  through  the 
bottom  of  the  tank  and  angled  over  for  easy  seeing.  By  such  an 
indicator,  much  more  is  accomplished.  The  operative  condition  of 
the  means  for  filling  the  tank  is  proved,  the  operator  can  not  guess 
that  the  tank  is  full  enough ;  he  must  fill  the  tank  to  get  an  indication, 
he  must  look  at  the  tank  structure  and  thereby  is  more  or  less  com- 
pelled to  inspect  it,  and  if  the  heat  has  failed  and  the  tank  frozen, 
the  top  of  the  sight  pipe  freezes  shut  and  the  tank  gives  warning  of 
ice  by  overflowing  around  the  top  of  the  tank  instead  of  at  the  sight 
pipe. 

G.  A.  SMITH1  (written).  The  paper  is  principally  an  abstract  of 
the  author's  specifications  covering  gravity  tanks  and  towers  prepared 
for  the  Associated  Factory  Mutual  Fire  Insurance  Companies  of 
Boston.  There  are  a  few  points  in  them  with  which  I  do  not  fully 
agree,  but  on  the  whole  consider  that  the  specifications  cover  the  field 
in  very  good  shape.  There  are  two  points,  however,  which  I  might 
mention  and  on  which  I  would  like  to  have  the  discussion  of  different 
members  of  the  Society: 

In  the  section  on  Towers  for  Elevated  Tanks,  Mr.  Teague  gives  a 
formula  for  unit  stress  in  water  tower  columns.  This  formula  gives 
a  unit  stress  of  12,000  Ib.  on  the  basis  of  90  radii.  It  has  always  been 
my  contention  that  a  higher  unit  stress  is  permissible  in  the  design  of 
water  tower  columns  for  the  reason  that  the  entire  load  is  quiescent 
and  is  entirely  dead  load.  There  might  be  some  question  raised  on 
this  point  due  to  the  fact  that  a  certain  portion  of  the  column  load  is 
caused  by  wind  pressure ;  however,  it  is  the  general  practice  to  permit 
a  higher  unit  stress  for  wind  loads  than  for  either  dead  or  live  loads. 

It  is  a  general  practice  of  most  engineers  in  the  design  of  steel 
structures,  such  as  bridges  and  buildings,  to  use  a  higher  unit  stress 
for  dead  loads  than  for  live  loads.  For  instance,  Theodore  Cooper 
specifies  for  bridges  a  unit  stress  in  chord  compression  members  of 
15,000  Ib.  for  dead  load  and  approximately  7000  Ib.  per  sq.  in.  for 
live  load,  both  of  these  stresses  being  based  on  90  radii.  On  a  similar 

1  Manager,  Des  Moines  Office,  Des  Moines  Bridge  &  Iron  Co.,  Des  Moines,  la. 


946  ELEVATED    TANKS 

basis,  I  believe  that  a  unit  stress  of  15,000  Ib.  per  sq.  in.  for  water 
tower  columns  is  conservative.  I  would  mention,  however,  that  on 
account  of  there  being  so  much  sentiment  against  this  high  unit  stress, 
the  company  which  I  represent  has  adopted  a  unit  stress  of  12,000 
Ib.  per  sq.  in.  for  columns  in  their  standard  water  tower  specifications. 

Another  point  on  which  I  do  not  quite  agree  with  Mr.  Teague  is 
the  expansion  joint  illustrated  in  his  paper.  The  illustration  is  not 
quite  clear  as  to  the  kind  of  metal  used  in  the  different  parts,  but  it 
is  his  requirement  to  use  cast  iron  in  the  pipe  sleeve  and  the  collar, 
and  brass  or  bronze  in  the  follower  and  adjustment  bolts.  I  contend 
that  this  expansion  joint  will  not  permit  proper  operation  after  it  has 
been  used  for  some  time.  It  is  my  idea  that  the  .cast-iron  sleeve  will 
corrode  or  rust  more  or  less  above  and  below  the  gasket,  and  in  fact 
will  corrode  to  some  extent  on  the  surface  covered  by  the  gasket. 
After  this  sleeve  has  become  more  or  less  corroded,  I  believe  that  it 
will  not  slide  freely  through  the  gasket,  and  in  fact  there  is  con- 
siderable danger  that  the  riser  pipe  would  probably  give  in  some  other 
point  before  sliding  in 'the  expansion  joint  as  intended.  I  cannot 
see  why  the  brass  follower  gland  used  by  Mr.  Teague  is  any  better 
than  a  cast-iron  gland  for  the  reason  that  the  clearance  between  the 
sleeve  and  the  follower  is  sufficient  to  prevent  any  serious  adhesion  by 
corrosion. 

My  idea  of  an  expansion  joint  which  would  always  work  freely, 
would  be  to  have  a  brass  covered  sleeve  instead  of  cast  iron  so  that  the 
surface  coming  in  contact  with  the  gasket  would  not  be  affected  by 
corrosion  and  therefore  would  slide  freely  through  the  gasket. 

C.  S.  PiLLSBURY1  (written).  Mr.  Teague  has  done  a  great  deal  to 
bring  about  the  general  adoption  of  proper  methods  in  the  design  and 
construction  of  sprinkler  tanks,  and  his  specifications  are  generally 
recognized  by  the  manufacturers  as  fairly  representing  the  best  present 
practice  in  that  class  of  work.  In  this  paper,  he  outlines  a  number  of 
suggestions  as  to  proper  unit  stresses,  plate  thicknesses,  etc.,  all  of 
which  tend  to  result  in  a  safe  and  economical  structure.  The  pro- 
visions which  prohibit  bolted  connections  and  reduce  the  shear  on  field 
rivets  are  especially  good. 

As  Mr.  Teague  says,  it  is  of  great  importance  to  design  the  details 
so  they  will  develop  the  full  strength  of  the  main  members.  To  those 
familiar  with  railroad  bridge  shop  practice,  this  statement  will  seem 

1  Chicago  Bridge  &  Iron  Works,  Chicago,  111. 


DISCUSSION  BY  C.  S.  PILLSBURY  947 

4* 

superfluous,  but,  as  a  matter  of  fact,  practically  every  failure  of  an 
elevated  tank  can  be  traced  to  an  eccentric  top  post  connection,  in- 
sufficient provision  for  the  horizontal  thrust  at  the  top  of  the  posts, 
poorly  made  column  splices,  or  some  other  oversight  due  to  inex- 
perience. To  prevent  excessive  stresses  in  the  tank  shell,  the  number 
of  posts  must  be  proportioned  to  the  diameter  and  depth  of  the  tank, 
and  provision  must  be  made  to  resist  the  torsional  moment  due  to  the 
curvature  of  the  sides.  It  is  also  necessary  to  provide  for  a  number 
of  severe  forces  other  than  gravity  and,  wind  loads.  This  last  state- 
ment is  well  emphasized  by  the  illustration  of  a  water  tower  loaded 
down  with  ice  due  to  the  continuous  overflowing  of  the  tank  in  cold 
weather.  It  is  only  a  carefully  designed  structure  that  can  undergo 
such  treatment  without  injury. 

Following  are  stress  formulae  used  by  the  Chicago  Bridge  &  Iron 
Works  which  may  be  of  interest  in  connection  with  Mr.  Teague's 
paper : 

Tank  Sides  and  Bottom.  The  stress  in  pounds  per  linear  inch  in 
the  sides  of  a  cylindrical  tank  is  2.6xHxD,  where  D  =  the  diameter 
of  the  tank  in  feet  and  H  —  the  head  of  water  in  feet.  The  maximum 
stress  in  a  hemispherical  bottom  is  1.3x77x1)  and  in  an  elliptical 
bottom  2.3xHxD.  The  last  two  formulae  are  closely  approximate,  H 
and  D  being  the  same  as  before,  except  that  in  this  case  H  should  be 
taken  as  the  total  depth  of  the  tank. 

Posts.  The  vertical  component  of  the  dead  load  post  stress  is  equal 
to  the  total  water  and  metal  load  divided  by  the  number  of  posts. 
The  vertical  component  of  the  wind  stress  equals  the  following : 


M 
3-post  tower 


4-post  tower 
6-post  tower . 


0.75  D 

M 
LOOP 

M  . 


8-post  tower 


2.001)       , 

where  M  =  moment  of  wind  about  panel  point  at  the  bottom  of  the 
post  section  considered  and  D  =  diagonal  of  towc^r  at^  the  panel  point, 
about  which  moments  are  taken. 


948  ELEVATED    TANKS 

Rods.     There  is  no  dead  load  stress  in  the  rods.     The  wind  stress 
equals  the  following: 

3-post  tower 0.500  (7-7')  Sec.  A 

4-post  tower 0.707  (V-V)  Sec.  A 

6-post  tower 1.000  (V-V)  Sec.  A 

8-post  tower 1.307  (7-7')  Sec.  A 

where  V  =  vertical  component  of  post  stress  in  panel  above; 

7  =  vertical  component  of  post  stress  in  same  panel  as  the  rod, 
and      A  =  angle  rod  makes  with  the  vertical. 

Struts.  Except  where  the  batter  of  the  posts  changes  there  is  no 
dead  load  stress  in  the  struts.  The  wind  stress  is  approximately  the 
horizontal  component  of  the  rod  stress  in  the  panel  below. 

THE  AUTHOR.  As  stated  in  the  paper  and  as  emphasized  by  Mr. 
Ketler,  the  possibility  of  danger  to  life  and  property  from  elevated 
tanks  is  greatest  when  they  are  erected  above  buildings.  I  fully  agree 
with  Mr.  Ketler  that  buildings  should  be  carefully  examined  by  a 
competent  engineer  to  ensure  that  they  will  safely  carry  the  load  to  be 
imposed  upon  them.  His  suggestion  that  a  standard  specification 
should  be  adopted  by  all  parties  interested  is  a  timely  one,  as  the 
recently  developed  specifications  of  the  Associated  Factory  Mutual 
Fire  Insurance  Companies  can  be  used  as  a  basis,  such  changes  or 
additions  being  made  as  seem  necessary  so  that  the  standard  will 
thoroughly  cover  all  conditions.  It  would  be  desirable  to  have  this 
Society  assume  the  leadership  in  the  work. 

Mr.  Freeman  also  advocates  uniformity  in  the  design  and  con- 
struction of  tanks  and  towers,  and  recommends  a  standard  specifica- 
tion following  along  the  lines  of  those  of  the  Factory  Mutual 
Companies. 

In  reply  to  Mr.  Blackburn's  suggestion  that  the  vertical  seams 
above  the  first  course  be  double  riveted,  I  have  -not  considered  it  neces- 
sary to  advise  this,  since  experience  with  the  single-riveted  joints  has 
thus  far  been  quite  satisfactory.  Certainly  if  much  trouble  from 
leakage  at  these  joints  should  be  experienced,  the  double  riveting 
would  be  advisable. 

Mr.  Hayes  has  brought  up  a  point  which  should  receive  more  care- 
ful treatment,  i.e.,  the  wind  load  on  the  tower  members  and  pipe 
fittings.  I  have  followed  current  practice  in  assuming  the  total  wind 
pressure  on  these  members  as  200  Ib.  per  linear  foot  height  of  tower 
and  have  not,  as  yet,  attempted  to  vary  the  pressure  to  suit  various 


CLOSURE  949 

heights  and  types  of  towers,  although  I  believe  that  this  is  advisable, 
especially  in  the  case  of  towers  to  support  tanks  for  other  uses,  such 
as  water  works'  supplies.  The  200  Ib.  pressure  gives  reasonably  ac- 
curate loadings  for  sprinkler  tank  towers,  as  the  height  of  these  is 
fairly  constant  within  limits.  A  closer  approximation  of  the  loading, 
even  for  these  towers,  would,  however,  be  appreciated  by  the  designing 
engineer. 

The  further  point  which  Mr.  Hayes  mentions,  that  the  actual  wind 
pressure  varies  according  as  to  whether  the  wind  blows  at  right  angles 
to  plane  of  the  bent  or  diagonally  is,  of  course,  correct,  especially  for 
angle-iron  towers.  As  a  further  refinement  in  determining  the  wind 
load  on  the  structure,  it  would  be  well  to  give  this  matter  con- 
sideration. 

Mr.  Blauvelt's  comments  regarding  the  use  of  the  overflow  to 
determine  if  the  tank  is  full,  represent  the  best  practice,  and  I  would 
say  that  the  use  of  a  mercury  gage  as  a  telltale  is  intended  merely  as 
a  constant  indication  of  the  water  level,  in  place  of  the  unreliable 
float  and  target  telltale  and  other  devices. 

In  reply  to  Mr.  Smith,  12,000  Ib.  per  sq.  in.  is  considered  a  proper 
maximum  allowable  unit  stress  in  compression  for  tank  towers  by 
most  manufacturers  and  engineers.  This  stress  is  none  too  conservative, 
in  view  of  the  very  special  type  of  tbe  structure  where  failure  of  one 
post  member  results  in  immediate  and  complete  collapse.  Further- 
more, the  towers  are  exposed  to  the  weather,  and  as  they  are  usually 
the  property  of  comparatively  small  companies  unfamiliar  with  the 
proper  care  of  steel  structures,  they  will  not  be  inspected  and  kept 
painted  as  will  steel  railroad  bridges  and  other  structures,  and  so  the 
steel  members  should  have  some  additional  thickness,  in  order  that 
they  may  remain  serviceable  even  after  some  considerable  corrosion 
has  taken  place. 

I  agree  with  Mr.  Smith  that  a  brass  or  brass  covered  pipe  at  the 
expansion  joint  is  preferable  to  the  iron  pipe  and  believe  that  this 
would  remove  the  last  possibility  of  binding  through  corrosion  in  the 
present  design.  This  improvement  may  be  secured  in  time,  but  the 
expansion  joint  shown  is  so  much  better  than  what  has  been  used 
that  it  seemed  wise  not  to  add  further  to  its  cost  at  this  time,  since 
there  undoubtedly  would  have  been  serious  objections  raised  by  the 
manufacturers  for  commercial  reasons.  The  advantage  of  the  brass 
follower  is,  of  course,  its  non-corrodibility,  which  will  permit  its  being 
moved  to  tighten  the  packing  even  if  the  iron  pipe  is  corroded,  as 


950  ELEVATED    TANKS 

mentioned  by  Mr.  Smith.  The  oil  lubricant  with  which  the  packing 
is  saturated  will  naturally  prevent  any  appreciable  corrosion  of  the 
pipe  where  it  bears  on  it  and  so  permit  of  movement  of  the  pipe  with- 
out injury  to  the  packing. 

The  suggestions  made  by  Mr.  Pillsbury  are  important  and  the 
data  which  he  has  given  regarding  stress  formulae  will  undoubtedly 
be  useful. 


No.  1424 

FIRE  PUMPS 

BY  EZRA  E.  CLARK/  BOSTON,  MASS. 
Non-Member 

Were  we  to  review  historically  the  development  of  fire  pumps,  we 
would  find  a  long  list  of  efforts,  dotted  frequently  with  failures,  and 
marked  here  and  there  with  a  partial  success.  No  sooner  does  man 
meet  fairly  well  the  fire  pump  requirements  of  an  age  than  he  finds 
he  must  make  a  still  better  apparatus;  for  in  the  march  of  human 
progress,  the  needs  of  fire  protection  always  keep  just  a  little  ahead 
of  the  provision  and  the  vigilance  of  man.  We  could  find  much  of 
interest  in  this  buried  history.  We  would  find  how  the  masterpiece 
of  some  old-time  mechanic  had  been  the  cherished  marvel  of  a  com- 
munity and  had  been  forced  by  a  rival  into  a  state  of  obsolescence. 
Even  the  fire  pump  of  today  will  sometime  become  an  obsolete 
device.  Nevertheless,  it  represents  the  present  state  of  the  art.  It 
is  the  pump  on  which  we  depend  to  stiffen  the  pressure  of  a  weak 
public  water  supply.  It  is  the  pump  from  which  we  expect  prompt 
and  reliable  service  in  the  extinguishing  of  fires.  It  is  the  business 
man's  concern  to  know  something  about  these  pumps,  their  possibili- 
ties, their  record,  which  one  of  the  various  types  should  be  selected 
for  a  given  situation,  and  how  to  install  them  so  as  to  secure  their 
best  service.  Are  not  these  vital  questions  for  the  man  who  ex- 
pects to  spend  a  limited  appropriation  for  fire  protection?  He  may 
ask,  "Why  do  I  need  a  fire  pump  when  I  have  a  tank  on  my  mill 
tower  and  a  6-in.  connection  to  the  public  main  ?" 

2  An  answer  to  his  question  may  be  found  in  the  history  of  the 
Paterson,  N.  J.,  fire,  eleven  years  ago,  where  a  group  of  six  mills  with 
their  own  fire  pump  protection,  checked  completely  the  conflagration 
sweeping  towards  them.  Each  mill  had  its  own  fire  pump  and  a 
stored  water  supply,  the  supplies  being  supplemented  in  some  cases 
by  a  connection  to  the  public  mains.  So  intelligently  were  these 
moderate  fire  equipments  handled  that  when  the  fire's  defeat  was  made 

Engineer  and  Inspector,  Factory  Mutual  Fire  Ins.  Cos. 


Presented  at  the  Annual  Meeting  1913,  of  THE  AMERICAN  SOCIETY  OF  ME- 
CHANICAL ENGINEERS. 

951 


952 


FIRE    PUMPS 


certain,  there  was  still  water  to  spare  in  the  pump  cisterns,  and  the 
mills  had  sustained  no  material  damage.  In  another  instance,  quite 
recent,  where  there  was  no  pump  but  simply  a  tank  and  a  moderate 
public  water  supply,  the  fire  ran  so  rapidly  through  the  building  that 
50  sprinkler  heads  opened,  and  several  fire  streams  were  quickly 
brought  into  service.  These  combined  drafts  on  the  water  supply 


FIG.  1     VIEW  OF  FIRE  STREAMS  FROM  CENTRIFUGAL  PUMPS 

so  reduced  the  pressure  that  neither  sprinklers  nor  fire  streams  were 
at  all  effective,  and  the  building  was  destroyed  with  a  loss  of  $8000, 
the  value  of  several  fire  pumps.  There  are  very  many  instances  that 
could  be  cited  where  the  prompt  starting  of  a  fire  pump  has  assured 
ample  pressure,  a  good  distribution  of  water  from  the  sprinklers  or 
several  effective  fire  streams,  and  a  comparatively  small  loss. 


EZRA    E.    CLARK 


953 


3  The  argument  is  being  advanced  today  that  because  90  per  cent 
of  our  fires  are  being  extinguished  with  perhaps  a  few  sprinkler  heads, 
rarely  requiring  the  service  of  a  fire  pump,  insurance  interests  are 
demanding  supplies  of  water  far  more  generous  than  is  reasonable, 
and  that  much  smaller  supplies  and  smaller  pipe  connections  would 
amply  suffice  to  give  reasonable  protection.  This  logic  is  attractive 
to  the  man  who  pays  for  the  equipment.  But  fires  have  a  way  of  pro- 
ceeding along  illogical  lines  and  it  is  the  wise  man  who  holds  himself 


FIG.  2     PART  SECTION  OF  EOTARY  PUMP,  TYPE  B 

prepared  for  the  illogical  and  the  unexpected  condition,  even  for  the 
worst  conceivable  condition,  the  doubtful  10  per  cent. 

DEFINITION   OF   TERM 

4  Broadly  speaking,  any  device  by  which  water  can  be  thrown  on 
a  fire  is  a  fire  pump.  In  its  simplest  form,  it  is  a  bucket  of  water  and 
a  man.  In  the  earliest  days  the  bucket  was  supplemented  by  huge 
syringes  in  the  form  of  a  bladder  or  bellows,  the  gut  of  an  ox  serving 
as  a  length  of  hose.  Later  they  were  made  from  brass  cylinders  and 


954 


FIRE    PUMPS 


were  called  "squirts."  From  these  crude  appliances  were  developed  the 
hand  and  steam  fire  engine  around  which  cluster  the  memories  of 
many  exciting  contests  during  the  last  century.  These  devices,  how- 
ever, are  all  portable  in  character,  and  valuable  time  is  often  lost  in 
bringing  them  to  the  scene  of  action. 


FIG.  3     WORKING  CAMS  OF  ROTARY  PUMP,  TYPE  B 

5  Manufacturing  properties,  particularly,  were  often  located  at 
such  a  distance  from  fire  engine  stations  that  prompt  service  was  im- 
possible. The  incalculable  value  of  a  few  gallons  of  water  at  the 
beginning  of  a  fire  became  self-evident,  so  that  pumps  fixed  upon  the 
premises,  connected  to  a  water  supply  and  a  source  of  power,  were 
introduced.  Later  these  were  connected  to  a  system  of  piping  about 


Slot -for  Inserting  small 
Screw  Driver  or  Jimmy 


Lug  Cc*f>ton 
Pump  End 


Section    H-H 


Set  Screw 
for  C lamping 
Collar  to  Shaft 


H  ^Driving  Pin 
Section  M-N-0 


FIG.  4    WATER  JOINT  USED  ON  ROTARY  PUMP  SHAFTS.  TYPE  B,  AS  SUBSTITUTE 

FOR  STUFFING  Box 

the  yard  and  in  the  mill,  and  the  pump  then  became  available  to 
supply  sprinkler  heads,  or  furnish  fire  streams  from  hydrants. 

6  In  this  paper,  the  term  fire  pump  is  to  be  used  in  its  restricted 
sense,  i.  e.,  a  pump  that  is  installed  in  a  fixed  position  for  fire  purposes. 
In  this  sense  there  are  three  or  four  distinct  types,  generally  acknowl- 


EZRA    E.    CLARK 


955 


edged :  rotary,  duplex,  centrifugal,  and  power  pumps,  any  one  of 
which,  of  course,  could  serve  as  a  fire  engine  by  mounting  it  on  wheels 
and  providing  a  source  of  power. 

TYPE   OF   PUMP 

7  The  type  of  pump  to  be  selected  should  be  determined  by  the 
character  of  power  available  for  the  purpose.  Naturally  the  most 
reliable  source  of  power  at  any  situation  would  be  chosen,  and  then  a 
pump  selected  that  can  best  be  driven  with  that  power.  This  should 
be  the  general  rule.  Every  type  of  pump,  however,  has  its  own  limita- 
tions and  these  must  be  kept  in  mind  when  studying  the  whole 


FIG.  5     TYPICAL  PRESS  FRAME  FOR  FRICTION  GEARS  DRIVING  ROTARY  PUMPS 

problem.  The  natural  selection  would  be  a  pump  that  can  run  at  or 
near  the  speed  of  the  prime  mover.  One  instance  has  been  noted 
where  a  centrifugal  pump  was  connected  to  a  waterwheel  through  a 
pair  of  spur  gears  having  a  ratio  of  5  to  1,  and  another  case  where  an 
electric  motor  was  connected  to  a  rotary  pump  through  spur  gearing 
having  a  ratio  of  1  to  5.  In  each  case,  the  pumps  took  their  suction 
supply  under  a  head.  Both  cases  may  be  dismissed  as  examples  of 
poor  engineering,  for  the  requirements  of  fire  service  would  have  been 
much  better  served  if  the  two  pumps  were  to  exchange  places  and 
the  reduction  gears  omitted,  thus  securing  the  simplest,  cheapest 
and  most  reliable  arrangement. 

8     The  earlier  mills  were  operated  almost  exclusively  by  water- 
wheels  and  their  usual  speed  made  it  comparatively  easy  to  connect 


956 


FIRE    PUMPS 


with  rotary  pumps.  Thus,  a  great  many  pumps  of  this  type  found 
their  way  into  the  wheel  pits  of  mills,  although  they  were  too  often, 
unfortunately,  poorly  located.  Power  plunger  pumps  were  used  in  a 
few  cases,  but  the  rotary  came  to  be  the  prevailing  pump,  owing  to  its 
simplicity,  cheapness  and  adaptability  to  the  prevailing  power.  Where 
waterwheels  of  ample  power  and  moderate  speed  are  available,  the 
rotary  type  of  pump  becomes  the  logical  choice,  for  the  two  can  often 
be  direct-connected,  or  some  simple  form  of  transmission,  such  as 


FIG.   6    EOTARY  PUMP,   TYPE  B,  PARTLY  DISMANTLED 


friction  gears,  or  a  silent  chain  having  a  low  speed  ratio  can  be  em- 
ployed. The  impulse  form  of  waterwheel  with  its  high  speed  would 
find  a  better  selection  in  the  centrifugal  pump,  requiring  no  inter- 
mediate gearing.  In  weighing  the  claims  of  the  several  pumps  for  a 
situation,  three  things  should  be  kept  in  mind:  the  character  of  the 
power  available,  the  limitations  of  the  pump  and  the  fact  that  the 
simplest  drive  is  the  best. 


EZRA  E.  CLARK 


957 


ROTARY  PUMPS 

9  Among  the  earlier  types  of  pumps  installed  in  mills  for  fire  pur- 
poses was  the  rotary.  There  are  so  many  indifferent  rotary  pumps  in 
mills  and  factories  that  the  mere  mention  of  a  rotary  raises  doubts  as 
to  its  value  for  fire  purposes.  Still,  it  should  be  remembered  that  even 
with  the  imperfect  construction  of  the  old  time  cast-iron  rotary,  they 
have  given  some  very  effective  service  at  critical  times.  However,  I 
invite  your  attention  not  to  these  obsolete  pumps,  but  to  that  product 
of  the  rotary  pump  builder  that  meets  the  present  insurance  specifi- 


FIG.  7     KOTARY  PUMP,  TYPE  B,  WITH  STANDARD  FITTINGS 

cations  and  notably  to  that  which  is  designated  as  Type  B  (Figs.  2 
and  3). 

10  Several  features  of  this  design  were  proposed  and  developed 
by  the  author  in  1904.  They  were  not  immediately  adopted,  as  some 
experimental  work  was  necessary,  and  new  patterns  were  required. 
These  new  features  were  chiefly  as  follows :  In  place  of  the  usual  two 
sets  of  overhung  cast-iron  gears,  one  extra-heavy  pair  of  cut  steel 
gears  is  substituted,  preferably  forged  solid  with  their  shafts;  these 
gears  are  supported  on  .either  side  by  generous  bearings,  and  the  two 
shafts  are  larger  and  stiffer;  all  bearings  are  provided  with  liberal 


958 


FIRE    PUMPS 


oil  reservoirs  and  ring  or  chain  oilers;  in  place  of  the  usual  stuffing 
boxes,  a  special  form  of  metal  water  joint  has  been  adopted,  which 
is  giving  excellent  service,  thereby  avoiding  the  use  of  perishable 
packing.  The  usual  fire  pump  features  are  also  provided;  viz., 
the  casing  and  working  parts  exposed  to  corrosion  are  of  bronze ;  there 
are  more  liberal  water  passages ;  the  working  cams  are  of  a  new  design 
to  insure  reasonably  smooth  running ;  and  the  usual  air  chamber,  hose 
connections,  an  approved  spring  relief  valve  and  starting  valve  com- 
plete the  arrangement.  The  press  frame  carrying  the  friction  gear 
is  now  fitted  with  a  heavy  spring  that  maintains  the  gears  in  contact, 


FIG.  8     SECTIONAL  VIEW  OF  UNDERWRITER  STEAM  FIRE  PUMP 

and  compensates  for  a  possible  lack  of  truth  in  their  running  ( Fig.  5 ) . 
11  These  pumps  are  not  intended  for  daily  service  as  the  wear 
between  cams  and  casing  would  soon  render  them  inefficient.  But 
for  the  brief  periods  of  fire  service,  considerations  of  wear  are  of  less 
importance  than  certainty  of  action.  Full  particulars  as  to  their 
construction  can  best  be  gathered  by  a  study  of  published  specifica- 
tions. The  effort  has  been  to  secure  a  rugged,  reliable  pump  capable 
of  doing  hard  work,  resisting  corrosion  and  withstanding  abuse.  These 
pumps  are  obtainable  today  from  at  least  two  manufacturers,  and  cost 


EZRA    E.    CLARK  959 

somewhat  less  than  a  duplex  pump.     The  limited  number  that  are 
already  in  the  field  are  so  far  giving  excellent  satisfaction. 

DUPLEX   PUMPS 

12  Where  steam  is  the  most  reliable  source  of  power,  the  duplex 
"Underwriter"  pump  is  usually  the  choice,  because  of  its  record  of 
proved  value.     It  is  also  much  the  cheapest  of  any  steam-driven  fire 
pump  of  acceptable  reliability,  selling  for  approximately  ten  cents  a 
pound.     In  spite  of  its  numerous  parts,  liable  to  derangement,  this 
pump  has  been  so  thoroughly  boiled  down,  so  to  speak,  that  with 
present  day  construction  it  is  proving  to  be  one  of  the  most  reliable 
of  fire  protection  appliances.     The  steam-turbine  driven  centrifugal 
pump  is,  of  course,  available  for  those  who  are  willing  to  pay  the 
price,  but  it  costs  approximately  twice  as  much.     Its  main  advantage 
over  the  duplex  is  its  simplicity  of  working  parts.    Its  disadvantages 
lie  in  the  fact  that  a  pressure  of  100  to  125  Ib.  of  steam  is  required 
for  good  results,  whereas,  with  a  duplex  pump,  50  Ib.  of  steam  is 
ample  for  ordinary  fire  pressures.     The  outfit  is  also  subject  to  the 
same  limitations  as  to  suction  lift  as  all  centrifugal  pumps.     When 
the  steam  turbine  centrifugal  has  become  standardized  and  its  price 
made  more  nearly  competitive  with  that  of  the  duplex,  no  doubt  it  will 
receive  a  much  wider  introduction. 

13  As  steam  began  to  supplement  and  in  cases  to  supplant  water 
power  in  mills,   steam-driven  pumps  were  installed  to  help  out  or 
replace  the  rotary.     At  first  the  single  cylinder  pump  was  used,  but 
the  advent  of  the  duplex  pump  marked  the  beginning  of  a  better 
machine  for  fire  purposes.     The  duplex  type  of  fire  pump  is  so  well 
known  that  it  is  hardly  necessary  to  describe  it,  full  information  as 
to  construction  being  available  in  published  specifications.    When  the 
development  of  the  Underwriter  type  of  duplex  pump  was  undertaken 
by  Mr.  John  E.  Freeman  in  the  early  nineties,  he  found  the  pump 
as  made  for  the  trade  lacking  in  several  features  needed  for  fire  pro- 
tection. The  frequent  failures  in  the  field  mainly  showed  that  improve- 
ment was  needed.     But  pump  builders  did  not  fully  sense  the  im- 
portance of  some  of  the  features  that  were  demanded,  and  more  or 
less  opposition  was  encountered. 

14  The  old  trade  duplex  pumps  were  found  with  steam  and  water 
passages  restricted,  but  these  have  been  enlarged  in  the  Underwriter 
type,  and  a  higher  speed  thus  made  possible.    The  trade  pumps  were 
iron  fitted  and  became  rusted   through  neglect,  so  that  they  could 
not   be   started;    the    Underwriter    pump    is    brass    fitted    wherever 


960  FIRE    PUMPS 

corrosion  is  liable  to  seize  the  working  parts.  In  the  older  pumps, 
cast-bronze  valve  stems  were  used  that  worked  loose  or  broke  off;  in 
the  present  Underwriter  standard,  these  stems  are  of  rolled  bronze 
and  made  heavier,  and  the  guard  is  so  secured  in  place  by  a  nut 
lock  devised  by  the  author  that  the  parts  cannot  work  loose 
(see  Fig.  9).  In  the  old  trade  pump  it  was  common  practice  to 
provide  means  of  adjustment  for  the  valve  motion,  and  this  adjust- 
ment sometimes  worked  loose,  or  was  tampered  with,  putting  the 
pump  in  a  lame  condition;  in  the  Underwriter  design,  all  adjustment 
has  been  ruled  out  and  a  simpler  and  more  reliable  mechanism  is  now 
used.  Special  fire  service  fittings  are  attached,  such  as  priming  valves, 
starting  valve,  relief  valve,  hose  valves,  oil  pump  and  lubricator,  all 
these  parts  having  been  subjected  to  examination  and  test  before  adop- 
tion. (See  Figs.  8  and  10.) 


FIG.  9    DETAIL  OF  VALVE  STEM  AND  SPECIAL  NUT  LOCK 

15  To  incorporate  these  changes  has  taken  time  and  it  has  been 
more  or  less  an  up-hill  job.     Experience,  however,  has  shown  the 
value  of  these  improvements  and  has  indicated  from  time  to  time  still 
further  improvements  which  have  been  adopted,  so  that  today  we  have 
a  fire  pump  that  is  able  to  start  at  a  moment's  notice,  run  at  full 
speed  if  needed,  and  when  supplied  with  steam,  water  and  oil,  will 
run  continuously  and  deliver  its  rated  capacity,  or  more,  against  a  fire 
pressure  of  75,  100,  150,  or  even  200  Ib.  in  special  cases. 

16  A  fire  pump  to  meet  these  conditions  must  be  rust-proofed.    It 
must  be  built  of  material  chosen  for  strength,  toughness  and  dura- 
bility.   It  must  be  so  free  from  complications  as  to  permit  of  operation 
by  men  of  moderate  ability.     It  must  be  able  to  withstand  safely  a 
large  measure  of  abuse,  and  be,  so  far  as  possible,  "foolproof."    This 
is  the  sort  of  steam  pump  tha,t  is  being  furnished  for  fire  protec- 
tion today.    It  is  not  claimed  that  the  pump  is  built  like  the  wonderful 


EZRA    E.    CLARK  961 

"one  boss  shay,"  equally  strong  in  every  part,  but  rather  from  specifi- 
cations that  make  the  possibility  of  failure  extremely  remote. 


ELECTRICALLY  DRIVEN  PUMPS 


17     Where  the  electric  motor  is  the  most  reliable  source  of  power, 
the  centrifugal  pump  naturally  becomes  the  choice.     The  speed  of  a 


FIG.  10     GENERAL  VIEW  OF  UNDERWRITER  STEAM  FIRE  PUMP 

centrifugal  pump  can  readily  be  made  to  conform  to  the  speed  of  the 
standard  motor  and  all  intermediate  gearing  avoided.  The  direct- 
connected  motor  and  pump  thus  form  the  simplest  possible  arrange- 
ment. It  has,  however,  certain  limitations  which  will  be  noted  later, 
and  there  may  exist  conditions  which  some  form  of  power  pump 
electrically  driven  would  meet  with  better  satisfaction. 


962 


FIRE    PUMPS 


18  Comparatively  few  power  pumps  are  in  use  as  fire  pumps,  owing 
to  their  highest  cost.  Their  best  field  is  where  a  daily  service  pump 
of  good  efficiency  is  needed,  that  can  in  the  emergency  be  used  for 
fire  purposes.  The  triplex  type  of  power  pump  is  much  to  be  preferred 
to  the  single  or  duplex  forms,  owing  to  its  steadier  discharge  pres- 
sure, and  as  it  is  usually  built  in  the  vertical  form  the  floor  space 
required  is  the  minimum.  A  strong  point  in  favor  of  the  triplex  power 


FIG.  11     VIEW  OF  TRIPLEX  POWER  FIRE  PUMP 

pump  as  compared  with  a  centrifugal  is  its  higher  efficiency,  running 
as  high  as  80  to  85  per  cent  for  outside  packed  plungers  as  against  the 
usual  65  to  70  per  cent  for  the  centrifugal.  That  type  of  triplex 
pump  employing  one  centrally  located  driving  gear  is  much  to  be 
preferred  to  those  having  two  overhung  gears.  Experience  has  shown 
that  the  central  gear  drive  will  better  ensure  an  even  distribution  of 
power,  and  thus  avoid  undesirable  stresses  on  gear  teeth  and  possible 


EZRA    E.    CLARK 


963 


breakage.  A  notable  example  of  the  central  gear  triplex  power  pump 
may  be  found  in  the  high-pressure  fire  service  station  in  Philadelphia, 
where  seven  such  pumps  are  operated  by  gas  engines,  and  have  given 
excellent  satisfaction  with  a  minimum  of  repairs. 

19  The  centrifugal  pump  is  comparatively  a  newcomer  in  the  fire 
pump  field.  It  is  distinguished  from  all  others. in  being  a  velocity 
pump,  the  pressure  varying  directly  as  the  square  of  the  peripheral 
velocity  of  the  impeller.  The  electric  motor  is  no  doubt  responsible 
for  its  coming  so  rapidly  into  favor.  The  constant  speed  motor  direct- 
connected  to  the  pump  makes  the  simplest  and  cheapest  arrangement 
and  affords  a  fairly  wide  range  of  capacities  and  pressures.  The 
variable  speed  motor  or  steam  turbine,  costing  a  little  more,  would 
place  the  pump  more  nearly  on  a  par  with  the  steam  duplex  as  to 
range  of  pressures,  and,  the  author  believes,  would  make  the  preferable 


FIG.  12     CENTRIFUGAL  FIRE  PUMP  WITH  DIFFUSION  VANES 


outfit.  Its  greater  cost,  and  complication  is  the  general  objection  to  it. 
20  There  are  two  types  of  centrifugal  fire  pumps  built,  one  with 
the  simple  cylindrical  case,  known  as  the  volute  pump,  and  the  other 
with  a  diffusion  vane  casting  or  chute  case.  The  diffusion  vane 
type,  sometimes  called  the  turbine  pump,  employs  a  series  of 
gradually  enlarging  passages  that  permit  a  more  gradual  change 
of  the  velocity  of  the  water  into  pressure  than  does  the  volute,  thus 
resulting  in  some  slight  gain  in  efficiency.  This,  however,  is  not  an 
essential  part  of  an  acceptable  fire  pump,  and  as  the  volute  type  of 
pump  (Fig.  13)  is  much  simpler  in  construction,  and  yields  efficiencies 
that  are  satisfactory  (60  to  70  per  cent),  this  type  of  centrifugal  fire 
pump  is  being  generally  adopted.  This  type  also  lends  itself  better  to 


964 


FIRE    PUMPS 


the  horizontal  division  of  casing,  which  is  preferred  to  the  circumfe- 
rential division,  as  it  permits  quicker  and  better  access  to  the  interior 
for  overhauling  or  cleaning. 

21  The  simplicity  of  the  centrifugal,  having  but  one  moving  part, 
appeals  to  every  engineer.  There  are  no  valves  to  choke  up,  no  plunger 
to  wear  out,  no  valve  motion  or  gears  to  break,  and  no  dangerous  pres- 
sures possible  even  with  all  outlets  closed,  unless  specially  provided 
with  a  variable-speed  prime  mover.  The  discharge  is  steady,  smooth, 
devoid  of  shocks,  and  more  nearly  approximates  that  from  a  gravity 
supply  than  any  other  pump.  But  it  has  its  limitations,  which  should 


FIG.  13     VOLUTE  TYPE  OF  CENTRIFUGAL  FIRE  PUMP 

be  fully  realized  and  considered  in  making  an  installation.  Unless 
provision  is  specially  made  for  a  variable  speed,  its  maximum  working 
pressure  is  usually  not  planned  to  be  very  much  above  100-lb.  pressure, 
running  for  the  smaller  flows  in  some  cases  up  to  130  or  140  Ib.  Con- 
sequently the  water  pressure  needs  of  a  situation  should  be  carefully 
studied  before  deciding  on  this  form  of  pumping  outfit,  and  if  higher 
pressures  are  needed,  either  a  special  form  of  impeller  should  be 
substituted  or  a  variable  speed  provided. 

Z2     A  centrifugal  has  no  power  to  exhaust  the  air  from  a  suction 
pipe,  as  has  the  rotary,  duplex,  or  other  displacement  pump.    For  this 


EZRA    E.    CLARK 


965 


reason,  the  suction  supply  should  come  to  the  pump  under  enough 
head  to  flood  the  pump  casing,  thus  insuring  its  being  primed.  If 
a  lift  is  unavoidable,  then  it  becomes  necessary  to  provide  a  suitable 
foot  valve  and  a  generous  supply  of  priming  water,  enough  to  fill  com- 
pletely the  suction  pipe  and  pump  casing.  This  feature,  of  course, 
limits  the  centrifugal  to  situations  where  there  are  easy  suction  supply 
conditions. 


Points  shown  are  test  readings. 


200       400 


1400       1600       1800 


600        800        1000      1200 
Gallons  per  Minute 

FIG.  14    CHARACTERISTIC  CURVE  FROM  TEST  OF  1000-GAL.  CENTRIFUGAL  FIRE 

PUMP 

23  Fig.  14  shows  a  characteristic  curve  obtained  by  actual  test 
from  a  1000-gal.  centrifugal  fire  pump.  It  will  be  noted  that 
at  its  rated  capacity  of  1000  gal.,  its  discharge  pressure  runs 
about  108  lb.,  and  at  half  capacity,  or  500  gal.,  it  runs  as  high  as  1£3 
lb.,  while  at  1500  gal.  the  pressure  drops  only  to  78  lb.  Thus  with  a 
constant  speed  motor  it  is  possible  to  get  a  good  range  in  discharge 
capacities,  50  per  cent  above  and  50  per  cent  below  the  rating,  and  all 
at  pressures  that  would  be  serviceable  for  fighting  fire. 


966 


FIRE    PUMPS 


24  The  curve  shown  is  approximately  what  is  desired  and  obtained 
in  the  average  two-stage  centrifugal.     For  some  situations  it  may  be 
desirable  to  secure  a  different  form  of  characteristic,  and  this  curve 
can  be  made  steeper  or  natter  within  limits. 

25  Where  two  pumps  are  to  operate  together  these  curves  should 
be  similar  and  the  characteristic  curves  should  be  known  and  posted 
in  view  of  the  operator,  in  order  that  he  may  intelligently  operate 
each  pump  to  perform  their  fair  share  of  the  work.     The  shut-off 
pressure  (no  discharge)  should  not  be  materially  below  the  maximum 
pressure,  at  the  top  of  curve.     For  pumping  against  a  constant  head, 
a  curve  approximating  a  horizontal  straight  line  would  naturally  be 
chosen. 

26  In  cost  the  centrifugal  pump  with  bedplate  is  but  little  more 


FIG.  15    EXAMPLE  OF  STEAM  TURBINE  DRIVEN  CENTRIFUGAL  FIRE  PUMP  UNIT 

than  the  duplex  per  pound,  but  the  addition  of  driving  motor  brings 
up  the  price  very  materially,  so  that  the  outfit  combined  costs  15  to  16 
cents  per  lb.,  and  weighs  about  the  same  as  a  duplex  pump.  For  a 
given  type,  the  speed  of  a  motor  determines  its  size  and  influences  the 
total  price  of  outfit.  It  may  roughly  be  stated  that  the  centrifugal 
pump  and  motor  costs  50  per  cent  more  than  the  duplex.  There  is  a 
wide  difference,  however,  in  the  weights  of  the  same  size  pump  among 
different  manufacturers. 

INSTALLATION 

27     In  a  brief  paper  like  this,  the  details  of  a  pump's  installation 
cannot  be  properly  reviewed,  and  yet  the  success  or  failure  of  a  fire 


EZRA    E.    CLARK  967 

pump  depends  very  much  on  its  being  properly  erected  and  connected 
up.  Briefly,  it  may  be  said  that  a  fire  pump  must  be  so  located  as 
to  be  safe  at  all  times  from  the  breakage  of  its  pipe  connections  due 
to  the  falling  of  floors  and  machinery,  and  safeguarded  from  any  in- 
fluence such  as  smoke,  fire  or  flood  that  might  drive  away  the  operator. 
It  should  be  accessible  at  all  times  for  operating  and  overhauling,  and 
not  blockaded  by  miscellaneous  storage.  It  must  permit  of  practicable 
pipe  connections,  the  suction  pipe  receiving  first  consideration,  and 
the  steam  and  discharge  pipes  so  run  as  to  be  safe  from  damage  and 
always  be  in  commission.  The  exhaust  should  go  direct  to  atmosphere, 
and  not  be  tied  up  with  other  pipes. 

28  The    suction    supply    should    preferably   be    practically   inex- 
haustible, such  as  a  river  or  lake,  and  a  suitable  intake,  properly 
screened,  provided.    Where  a  stored  supply  only  is  available,  it  should 
be  large  enough  to  supply  the  pump  for  two  hours,  more  or  less,  de- 
pending on  conditions.    No  cast-iron  rules  can  well  be  established  as 
the  insurance  engineer  having  jurisdiction  is  expected  to  weigh  con- 
ditions, and  secure  a  reliable  pump  service  without  expensive  or  com- 
plicated refinements.     Full  details  as  to  pump  installation  have  been 
covered  in  the  several  publications  and  specifications  which  from  time 
to  time  have  been  developed  in  the  Factory  Mutual  Inspection  De- 
partment. 

29  It  will  perhaps  be  of  interest,  and  not  altogether  without  value, 
to  look  a  bit  into  the  future  and  try  to  discern  what  is  to  be  the 
development  of  the  fire  pump.    It  is  not  at  all  unlikely  that  the  steam 
turbine  centrifugal  will  gradually  displace  the  duplex  pump,  as  its 
design  becomes  simplified  and  standardized,   and  its  cost  lowered. 
Where  steam  is  not  available,  we  shall  find  the  electric-driven  centrifu- 
gal, or  the  gasolene-driven  rotary,  and  as  fast  as  its  development  per- 
mits, the  gas-turbine-driven  centrifugal  will  possibly  win  recognition 
and  receive  adoption.     To  whatever  extent  insurance  interests  adopt 
these  new  appliances,  it  will  be  done  with  an  eye  single  to  their  proved 
value,  as  regards  simple  and  rugged  construction  and  reliability  of 
performance. 

DISCUSSION 

ALFRED  B.  CARHART.  Upon  the  practical  side  of  the  operation  of 
fire  pumps,  I  think  the  author  of  this  paper  has  called  attention,  in 
one  of  the  final  paragraphs  on  Installation,  to  a  very  important  con- 
sideration, which  was  not  mentioned  in  the  presentation  of  the  paper. 


968  FIRE    PUMPS 

It  is  such  a  simple  matter,  that  it  seems  surprising  that  engineers  in 
laying  out  new  plants,  will  connect  the  exhaust  of  steam-operated  fire 
pumps  with  other  exhaust  lines,  and  then  supply  stop  valves  by  which 
these  pipes  can  be  cut  oft  from  the  exhaust  line  to  prevent  back- 
pressure and  condensation,  not  realizing  that  when  the  fire  pump  is 
needed  in  a  hurry,  it  will  be  impossible  to  operate  it  effectively,  be- 
cause there  will  be  no  free  outlet  for  the  exhaust  steam.  Such  con- 
ditions have  been  discovered,  much  to  the  chagrin  of  those  in  charge 
of  otherwise  admirably  constructed  plants. 

ALBERT  BLAUVELT  (written).  Eeferring  to  the  section  of  Mr. 
Clark's  paper  on  electrically  driven  pumps,  it  is  my  observation  in  the 
field  that  the  electric  motor  centrifugal  pump  is  as  yet  considerably 
short  of  working  development  as  compared  to  the  Underwriters'  steam 
fire  pump.  The  steam  pump  is  a  self-contained  affair  including  the 
more  essential  fittings,  and  ordinarily  is  handled  successfully  when 
needed.  The  electrically  driven  pump  thus  far  appears  always  to 
require  considerably  more  skill  and  sense  of  time  on  the  part  of  the 
operator.  The  motors  are  excellent  and  so  are  the  pumps,  but  neither 
pump  maker  nor  motor  maker  appears  to  know  each  other,  nor  do 
either  appear  prepared  to  deliver  a  complete  pumping  set,  fully  fitted 
and  adapted  to  unfamiliar  and  incompetent  handling  in  a  degree 
comparable  to  the  steam  pump.  Meantime,  mismoves,  or  delay  or 
total  failure  of  starting,  mark  the  attempt  of  watchmen  or  other  men 
not  trained  to  the  electric  pump.  I  take  no  pride  in  the  various  elec- 
tric pumps  installed  in  our  practice  thus  far,  and  have  less  esteem  for 
similar  jobs  set  up  under  other  auspices.  Doubtless  as  the  trade  in- 
creases some  shop  will  put  out  a  complete  and  self-contained  electric 
pump,  with  fittings  interlocked  or  timed  against  mismoves. 

THE  AUTHOR.  From  the  remarks  of  Mr.  Blauvelt,  it  appears  that 
he  finds  that  men  not  trained  to  the  electric  pump  make  mismoves,  or 
totally  fail  to  start  the  pump.  This  is  also  true  of  men  not  trained 
to  steam  or  rotary  pumps. 

It  should  be  remembered  that  the  steam  fire  pump  has  been  grow- 
ing up  with  us  for  40  or  50  years,  and  there  is  a  larger  number  of 
average  men  familiar  with  such  apparatus  than  there  is  familiar  with 
the  electrically  driven  centrifugal  pump.  The  latter  has  been  with 
us  but  a  few  years,  and  for  the  average  man  it  is  still  somewhat  of  a 
novelty  that  he  but  vaguely  comprehends. 


CLOSURE  969 

A  remedy  for  this  situation  does  not  appear  to  be  getting  the  pump 
maker  to  know  better  the  motor  maker.  It  is  rather  for  the  pump 
operator  to  know  better  the  apparatus  under  his  charge.  It  has  not 
been  found  necessary  for  rotary  pump  builders  to  furnish  the  water- 
wheel  driving  the  pump,  nor  has  it  been  necessary  for  steam  pump 
makers  to  go  into  the  steam  boiler  business. 

The  troubles  arising  from  centrifugal  outfits  are  mainly  due  to 
errors  in  installation,  or  a  failure  to  realize  the  limitations  as  well  as 
the  possibilities  of  this  type  of  pump. 

A  properly  installed  centrifugal  and  motor  is  one  of  the  simplest 
of  fire  pumps,  and  easy  to  start.  Eegarding  interlocking  devices  to 
prevent  mismoves,  these  are  but  complications  that  add  to  the  con- 
fusion of  the  operator.  A  simple  device  under  intelligent  control  is 
much  to  be  preferred  to  automatic  control  involving  added  complica- 
tions. It  is  not  necessary  for  a  man  to  be  an  electrician  in  order  to 
operate  a  motor  driven  centrifugal,  any  more  than  it  is  necessary  for 
a  steam  pump  operator  to  be  an  expert  in  hydraulics,  pneumatics, 
and  the  use  of  steam.  But  he  does  need  to  know  something  about 
these  matters  in  either  case,  and  especially  to  know  the  use  of  the 
fittings  and  devices  that  he  sees  before  him.  There  is  no  positively 
certain  way  to  prevent  an  incompetent  man  from  making  the  fool 
move. 

There  will  no  doubt  be  improvements  made  from  time  to  time 
based  on  experience  tending  to  standardize  these  outfits,  which  will 
simplify  their  operation;  but  the  lack  of  confidence  in  present  ap- 
paratus which  is  expressed  by  the  gentleman  is  not  shared  by  the 
author. 


No.  1442 

FLOOR  SURFACES  IN  FIREPROOF 
BUILDINGS 

BY  SANFORD  E.  THOMPSON,  BOSTON,  MASS. 
Member  of  the  Society 

In  fireproof  construction,  whether  it  be  office  building,  factory, 
or  institution,  the  question  of  the  type  of  floor  surface  to  select  and 
the  method  of  construction  to  adopt  is  a  most  important  one.  The 
constant  tread  and  shuffling  of  feet  cause  a  friction  that  it  is  difficult 
to  withstand  without  serious  wear. 

2  From  the   construction  standpoint,   in   a  non-combustible 
structure  a  cement  surface  is  in  keeping  with  the  rest  of  the  building 
and  is  naturally  the  first  considered.    In  many  instances  the  cement 
concrete  or  granolithic  floor   has  proved  extremely  satisfactory, 
while  in  others,  because  of  the  use  of  improper  constituents,  of  in- 
expert construction,  or  of  its  selection  for  places  to  which  it  is  not 
adapted,  it  has  proved  a  disappointment.    As  a  matter  of  fact,  no 
one  type  of  floor  surface  is  adapted  to  all  conditions,  while  for  any 
type  that  is  properly  selected,  the  choosing  of  the  materials  and  the 
manner  of  the  construction  will  govern  to  a  large  extent  the  dura- 
bility of  the  surface. 

3  It  is  the  purpose  of  this  paper  to  discuss  briefly  the  different 
kinds  of  floor  surfaces,  and  to  compare  their  various  qualities,  their 
cost,  and  their  adaptability  to  specific  conditions.     This  is  followed 
by  a  more  detailed  treatment  of  the  methods  of  constructing  the 
concrete  or  granolithic  surface  which  have  produced  satisfactory 
results.   ;;<&  , 

4  An  engineer  in  consulting  practice  is  called  upon  frequently 
not  only  to  design  and  construct  but  to  investigate  defective  con- 
struction and  also  to  make  special  tests  for  the  determination  of  the 
best  methods  to  employ  in  a  particular  case.     In  this  paper  are  em- 
braced not  only  the  results  of  experience  in  floor  construction  and 
repairs,  especially  as  they  relate  to  granolithic  surfaces,  but  also  the 

--Presented  at  the  Annual  Meeting,  December  1914,  of  THE  AMERICAN  SO- 
CIETY OF  MECHANICAL  ENGINEERS* 

387 


388  FLOOR   SURFACES   IN   FIREPROOF   BUILDINGS 

conclusions  derived  from  special  tests  and  investigations  made  in 
connection  with  services  as  consultant  on  the  superstructure  of  the 
New  Technology  buildings  in  Cambridge. 

5  Embodied  in  the  paper  is  much  of  the  material  forming  a 
report  to  the  Stone  &  Webster  Engineering  Corporation,  engineers 
and  builders  of  New  Technology.  The  matter  covered,  then,  will 
include : 

Discussion  of  selection  of  type  of  floor  surface 

Relative  costs  of  various  floor  surfaces 

Characteristics  of  floor  surfaces 

Tests  and  investigations  of  granolithic  construction 

Recommendations  for  granolithic  construction 

SELECTION    OF   TYPE   OF   FLOOR 

6  The  selection  of  the  type  of  floor  is  dependent  on  the  char- 
acter of  the  structure,  the  nature  of  the  wear,  and  the  architectural 
appearance.     Every  building  must  be  considered  by  itself.     Sug- 
gestions for  the  type  of  surface  to  select  are  covered  in  the  following 
pages.     As  a  preliminary  guide,  the  material  suitable  for  different 
conditions  may  be  given  as : 

Basements:  Granolithic  finish  with  trowelled  surface  made  with  approved 
materials  and  workmanship. 

Factory  Floors:     Granolithic  finish  with  trowelled  surface;  hardwood. 

Machine  Shops:  Granolithic  finish  with  trowelled  surface;  hardwood  on 
substantial  base. 

Ground  Floors  for  Heavy  Manufacturing:     Wood  block;  granolithic. 

Warehouses:  Granolithic  with  trowelled  surface;  asphalt  composition; 
hardwood.  • 

Offices:     Hardwood;  linoleum  on  concrete;  magnesium  composition. 

Corridors  and  Halls  for  institutions  and  office  buildings:  Terrazzo;  grano- 
lithic finish  with  ground  surface. 

Entrance  Pavilions:     Terazzo;  mosaic;  tile;  natural  stone. 

Class  Booms,  Lecture  Booms,  and  Drawing  Booms:  Linoleum  on  concrete; 
granolithic  with  ground  surface;  hardwood;  magnesium  composition. 

Laboratories:  Granolithic  with  trowelled  surface;  magnesium  composition; 
tile;  hardwood. 

Lavatories:     Terrazzo;  granolithic  finish  with  ground  surface;  tile. 

The  above  selections  are  given  in  the  order  in  which  choice  might  be 
made  for  the  average  building  or  room  of  each  class. 

APPROXIMATE  COST  OF  VARIOUS  FLOOR  SURFACES 

7  In  giving  approximate  costs  of  floors  it  is  recognized  that  the 
condition  of  the  market  both  in  labor  and  materials  and  the  quality 


SANFORD   E.   THOMPSON  389 

of  the  materials  selected,  affects  the  unit  price  to  a  very  large  degree; 
also  the  location,  size  and  shape  of  the  rooms  to  be  finished. 

8  The  following  prices  are  based  on  estimates  of  cost  in  place. 
For  the  materials  like  hardwood  that  are  laid  after  the  partitions  are 
placed,  the  prices  apply  more  particularly  to  a  building  such  as  a 
college  or  other  institution  divided  into  offices  and  rooms  of  various 
sizes.  Each  price  is  assumed  to  include  total  cost  of  the  labor  and 
material,  exclusive  of  the  structure  itself.  It  is  assumed  that  the 
base  upon  which  the  floor  is  laid  is  either  structural  concrete  or  some 
similar  material. 

Cost  per  sq.  ft. 
Granolithic: 

If  laid  at  same  time  as  base,  with  trowelled  surface $0.05 

If  laid  at  same  time  as  base,  with  ground  surface 0 . 08 

If  laid  after  completion  of  base,  and  trowelled 0.07 

If  laid  after  completion  of  base,  and  ground 0.10 

Linoleum : 

Battleship  linoleum  including  $0.03  per  sq.  ft.  for  placing 
and  trowelling  a  %-in.  layer  of  mortar  immediately 
after  base  concrete  is  laid,  linoleum  being  figured  at 

$1.30  per  sq.  yd.,  cemented  in  place 0 . 18 

Hardwood  : 

Maple  or  birch,  single  thickness,  including  $0.01  for  level- 
ing off  base  concrete  and  including  stringers  with 

cinders  between,  with  rough  1-in.  floor  underneath 0.22 

Maple  or  birch,  single  thickness,  including  $0.01  for  level- 
ing off  base  concrete  and  including  stringers  with 

cinders  between 0 . 18 

Maple  or  birch,  single  thickness,  including  $0.01  for  level- 
ing off  base  concrete  and  including  stringers  with 

cinders  between,  with  rough  2-in.  floor  underneath 0 . 25 

These  prices  are  based  on  good  quality  of  hard  wood  at  about  $45  per  1000  ft.  B.  M. 

Terrazzo  : 

With  small  stone  %  in.  to  %  in.  including  $0.01  for  level- 
ing the  base  concrete 0 . 19 

With  large  stone  %  in.  to  1  in.  including  $0.01  for  leveling 

the  base  concrete 0 . 24 

For  areas  of  50,000  sq.  ft.  or  more,  deduct  10  per  cent  from  these  figures. 

Base  6  in.  high 0.36-0.50  per  lin.  ft. 

Marble  Mosaic: 

Grouted  and  ground 0 . 50-0 . 60 

Magnesium  Composition  : 

For  large  areas,  say  100,000  sq.  ft.,  including  $0.01  for  level- 
ing base  concrete 0 . 20 

For  small  areas,  say  25,000  sq.  ft.,  including  $0.01  for  level- 
ing base  concrete 0 . 24 


390  FLOOR   SURFACES   IN   FIREPROOF   BUILDINGS 

Asphalt  Flooring: 

Including  $0.01  for  leveling  base  concrete 0. 15-0. 17 

Asphalt  Mastic: 

For  areas  100,000  sq.  ft.  or  more  including  $0.01  for  level- 
ing base  concrete 0 . 15-0 . 16 

In  chemical  laboratories 0 . 17-0 . 18 

6-in.  sanitary  base, 0.25  per  lin.  ft. 

Tile: 

Quarry  tile 0 . 35-0 . 40 

Fancy  pattern  tile 0 . 50 

Cork  Tile: 

Moravian  tile,   fancy  pattern 0 . 75-1 . 25 

CHARACTERISTICS  OF  FLOOR  SURFACES 

9  Granolithic  Trowelled.     As  ordinarily  laid  in  buildings,  grano- 
lithic or  concrete  surfaces  are  subject  to  dusting  and  under  heavy 
traffic,  such  as  trucking,  are  liable  to  serious  wear.     On  the  other 
hand,  experience  with  first-class  construction  and  tests  of  actual 
floors  shows  that  it  is  possible,  by  proper  selection  of  the  aggregates 
and  expert  workmanship,  to  reduce  the  dusting  to  an  insignificant 
amount  and  to  produce  a  surface  hard  enough  to  stand  even  severe 
wear. 

10  For  factory  floors,  notwithstanding  many  cases  of  inferior 
construction,  the  use  of  granolithic  is  largely  increasing.     It  is  be- 
coming recognized  that  the  durability  of  granolithic  is  in  a  very  large 
measure  dependent  upon  the  sand  or  other  aggregates  used  in  the 
construction  and  the  methods  of  laying  it. 

11  The  chief  objection  to  concrete  or  granolithic  surfaces  for 
offices,  drafting  rooms,  class  rooms,  and  certain  laboratories,  is  that 
it  is  dull  in  appearance,  hard  on  the  feet  for  men  standing  all  day, 
tends  to  break  tools  dropped  upon  it,  and  is  not  adapted  to  attaching 
seats  and  other  furniture  readily,  especially  where  they  have  to  be 
shifted  occasionally.     In  certain  colleges,  however,  concrete  surfaces 
are  used  widely  and  highly  recommended.     At  Bowdoin  and  at 
the  University  of  Wisconsin  it  is  considered  satisfactory  for  all  pur- 
poses.    At  the  University  of  Missouri  the  newer  buildings   are   all 
being  built  with  granolithic  surfaces.     In  some  colleges  granolithic 
is  being  satisfactorily  used  for  corridors.     Most  of  the  colleges  favor 
granolithic  for  chemical,  mining,  and  mechanical  laboratories.     The 
Leland  Stanford,  Jr.,  University  states  that  in  the  mechanical  and 
engineering  laboratories  the  men  complain  of  hardness  and  coldness, 
requiring  wood  platforms  in  many  places.     In  this  university,  how- 


SANFORD   E.    THOMPSON  391 

ever,  granolithic  has  been  used  in  the  chemical  laboratories  for 
15  years  with  excellent  satisfaction.  It  should  be  noted,  further, 
that  in  the  mechanical  and  engineering  laboratories  the  floor  rests 
directly  on  the  ground,  while  in  the  chemical  laboratory  there  is  a 
warm  room  or  basement  underneath. 

12  The  life  of  a  well  laid  granolithic  surface  under  foot  traffic  is 
practically  permanent.     Tests  of  various  materials  and  methods  are 
discussed  elsewhere  in  this  paper,  and  specifications  are  given  in 
appendices  for  durable  granolithic  surfaces. 

13  Granolithic  with   Ground   Surface.     Experimental   surfaces, 
together  with  laboratory  tests  made  as  a  check,  show  that  a  pleas- 
ing surface,  approaching  terrazzo  in  appearance  and  fully  as  dur- 
able under  foot    traffic,   can  be  obtained  by  placing  granolithic 
with  scarcely  any  trowelling,  and  then  grinding  the  surface  just 
enough  to  expose  the  grains  of  sand  and  stone.     The  grains  which 
show  are  finer  than  in  terrazzo  and  darker  colored.     The  appearance, 
however,  is  pleasing.     Removal  of  the  scum  takes  away  the  monotony 
of  the  plain  gray  cement  surface,  since  this  is  relieved  by  the  various 
colors  of  the  sand  and  stone.     A  glossy  effect  can  be  produced  if  de- 
sired by  the  grinding  which  permits  of  easy  cleaning  and  gives  a 
surface  suitable  even  for  a  lavatory  at  much  less  cost  than  tile  or 
terrazzo.     Still  further  to  give  variety  to  the  appearance,  tile  can  be 
placed  in  patterns  or  as  a  border. 

14  The  University  of  Missouri,  which  refers  to  the  dust  from 
granolithic  floors,  believes  that  this  difficulty  would  be   solved   by 
grinding  the  surface  instead  of  trowelling.     Specifications  giving  the 
method  of  laying  the  concrete  granolithic  and  grinding  it  are  pre- 
sented at  the  end  of  this  paper.     From  observations  of  the  time 
required  for  grinding  the  surfaces  and  allowing  amply  for  delays,  the 
extra  cost  for  grinding  is  estimated  not  to  exceed  3c.  per  square  foot 
of  surface  area. 

15  Linoleum.    The  hardness  and  noise  characteristic  of  grano- 
lithic finish  are  overcome  by  covering  the  surface  with  Battleship 
linoleum.     In  the  few  colleges  where  this  has  been  adopted  they  are 
very  enthusiastic  over  the  results.     In  other  places,  such  as  offices, 
the  same  type  of  construction  meets  with  a  great  deal  of  favor. 
At  the  University  of  Chicago  cork  carpets  are  used,  which  answer  a 
similar  purpose. 

16  Linoleum  is  laid  on  a  concrete  surface,  which  need  not  be 
brought  to  a  fine  finish  and  therefore  can  be  completed  at  the  time 


392  FLOOR    SURFACES   IN    FIREPROOF   BUILDINGS 

the  base  concrete  is  laid  and  at  a  low  cost.  Any  marring  of  the 
surface  or  sudden  rains  will  not  affect  its  use  for  the  linoleum  finish. 
17  The  linoleum  should  be  stuck  firmly  to  the  granolithic 
surface  and  preferably  a  cove  base  should  be  run  around  the  room 
and  sills  provided  at  entrances  so  that  the  surface  of  the  granolithic 
will  be  flush.  In  this  way  the  edges  are  prevented  from  fraying. 
The  life  of  first-class  quality  Battleship  linoleum,  if  edges  are  not 
frayed,  is  probably  from  15  to  30  years,  depending  upon  the  amount 
of  travel.  These  ages  are  estimated  from  records  of  linoleum  now 
in  use. 

1  18  Linoleum,  after  allowing  for  the  better  finish  required  on  the 
concrete,  costs  substantially  the  same  as  a  single  floor  of  birch  or 
maple,  but  it  is  noiseless,  more  uniform  in  appearance,  and  requires 
less  labor  for  maintenance  in  good  condition.  Its  superiority  to 
wood  is  indicated  by  the  fact  that  wood  floors  are  frequently  covered 
with  linoleum. 

19  Hardwood  Floors.    Floors  of  maple,  birch,  beech,  oak,  or 
long  leafed  Southern  pine  are  used  most  largely  for  offices,  classrooms, 
or  lecture  rooms,  and  in  many  of  the  older  colleges  for  laboratories 
and  halls.     A  wood  surface,  however,   is  not  usually  considered 
entirely  satisfactory  either  in  general  appearance  or  in  wearing 
qualities.     If  one  passes  from  a  corridor  with  a  granolithic,  terrazzo, 
or  tile  floor,  into  a  room  or  auditorium  having  a  wood  floor,  there  is  a 
marked  effect  of  inferiority  and  cheapness.     There  is  just  as  much 
danger  of  poor  materials  and  workmanship  with  wood  as  with  other 
kinds  of  floors.     Unless  the  greatest  care  is  taken  in  selection  of 
materials  and  workmanship,  they  are  liable  to  shrink  or  swell  and 
sometimes  to  squeak  under  foot.     If  at  all  hollow  underneath,  they 
are  more  noisy  than  a  concrete  surface.     The  floors  of  the  New 
Grand  Central  office  buildings  are  an  example  of  this. 

20  For  corridors,  wood  is  being  largely  superseded  by  granolithic, 
terrazzo,  or  tile.     For  laboratories  other  materials  are  being  sub- 
stituted for  wood  in  most  of  the  newer  structures,  although  wood  is 
occasionally  preferred,  especially  for  physical  laboratories  and  for 
laboratories  where  men  stand  for  long  periods.     The  linoleum  on 
concrete  will  overcome  practically  all  the  objections  that  are  made 
to  wood  floors,  with  a  cost  substantially  the  same. 

21  There  are  various  methods  of  laying  hardwood  floors.     For 
classrooms  a  single  thickness  of  maple  or  birch  nailed  to  sleepers 
with  cinder  concrete  between  should  be  satisfactory.     Another  type 
of  construction  is  to  use  patented  metal  screeds  embedded  in  the 


SANFORD   E.   THOMPSON  393 

base  concrete,  and  nail  the  floor  boards  to  splines  in  the  screeds. 
For  rooms  subjected  to  heavy  traffic,  2-in.  or  2J^-in.  plank  may  be 
placed  underneath  the  hardwood  floor. 

22  Of  all  the  different  materials,  oak  is  the  most  expensive  and 
the  finest  in  appearance  at  the  beginning,  but  under  heavy  traffic 
is  more  liable  to  splinter  than  the  finer  grained  woods.     Georgia 
pine,  if  of  best  quality,  makes  a  durable  floor,  and  is  preferable  to 
the  finer  grained  woods  in  wet  places,  as  it  does  not  swell  and  warp 
so  badly.     It  is  less  durable,  however,  and  therefore  not  recom- 
mended for  the  greatest  permanence  in  rooms  such  as  class  and  lecture 
rooms.     Maple,  birch,   and  beech,   all  make   good  floor  material. 
These  are  usually  laid  in  strips  ^-in.  thick  by  2%-in.  wide.     The 
quality  varies  largely,    ranging  in  cost  from  $32  per  1000  to  $75 
per  1000. 

23  Terrazzo.     Terrazzo    is  made  by  spreading  upon  the  base 
concrete  a  mixture  of  neat  cement  and  marble  chips  and  grinding 
the  surface  to  a  depth  sufficient  to  cut  into  stones  and  expose  them 
on  their  largest  diameters.     Marble,  sometimes  white  and  some- 
times colored,  is  used,  and  since  no  sand  is  employed  the  particles 
may  be  of  fairly  uniform  size.     The  joints  between  the  particles 
being  of  neat  cement  are  hard  and  even  more  durable  than  the 
pieces  of  the  marble  themselves.     Large  pieces  of  marble,  from 
%-in.  to  1-in.  in  diameter,  give  a  more  distinctive  floor  but  cost  more 
than  a  floor  of  the  smaller  stones,  from  y^-m.  to  3/£-in.  in  diameter, 
because  the  large  stones  require  much  more  grinding  to  get  down  to 
the  large  diameters  of  the  particles.     There  is  more  tendency  to 
crack  than  in  a  good  granolithic  properly  bonded  to  the  base,  but 
if  laid  with  the  best  workmanship,  this  cracking  is  reduced  to  a 
minimum. 

24  Terrazzo   is   largely    used,    especially   in   the   newer   office 
buildings  and  in  institutions,    for  corridors  and  halls.     It  also  is 
satisfactory  for  lavatories,    although  more  expensive  than  grano- 
lithic.    It  appears  from  our   investigation  that  for  both  of  these 
uses  concrete  with  a  ground  surface  can  be  substituted  at  less  cost 
and  with  satisfactory  results. 

25  In  certain  cases  objection — which  applies  also  to  any  hard 
material  like  granolithic  or  tile — is  raised  to  terrazzo  because  of  the 
noise,  and  even  corridors  are  covered  with  linoleum  or  similar  ma- 
terial. 

26  Marble  Mosaic.    Mosaic  consists  of  small  squares  of  marble 
laid  on  the   cement   bed,   something   like  terrazzo.     Surfaces   are 


394  FLOOR   SURFACES   IN   FIREPROOF   BUILDINGS 

ground  enough  to  make  all  pieces  true  and  level.  The  price  of 
mosaic  is  too  high  to  be  considered  for  large  areas  and  in  many 
cases  the  pieces  of  marble  pull  out  from  the  surface.  Mosaic  is 
suitable  in  certain  cases  for  an  ornamental  border  which  is  not 
subject  to  wear. 

27  Magnesium    Composition.     When    laid    with    great    care, 
composition  is  a  satisfactory  and  durable  material.     Floors  6  or  8 
years  old  have  been  examined  and  show  satisfactory  wear.     The 
work  must  be  done  by  a  responsible  firm  with  a  suitable  guarantee 
bond,  because  even  with  the  greatest  care  the  work  is  occasionally 
imperfect.     The  imperfections,  however,  are  apt  to  show  within  the 
first  year  of  service.     Composition  is  more  resilient  than  granolithic, 
so  that  there  are  less  complaints  of  hardness.     It  is  nearly,  but  not 
quite,  as  noisy.     Furniture  can  be  screwed  directly  to  the  com- 
position. 

28  Composition  has  not  yet  been  used  to  a  great  extent  in 
colleges.     The  floors  of  Cooper  Union  in  New  York  City  are  many  of 
them  covered  with  this  material  and  the  results  have  been  satis- 
factory.    It  is  suitable  for  certain  laboratories,  such  as  physical  and 
biological. 

29  Asphalt  Composition.     Asphalt  composition  is  suitable  for 
certain  places  where  no  heavy  tools  or  machines  are  liable  to  press 
into  the  soft  surface.     It  is  resilient  and  easy  to  walk  and  stand  upon. 
The  color  is  not  pleasing,  being  a  dead  black.     In  a  few  colleges 
it  has  been  used  satisfactorily  for  chemical  laboratories.     At  Harvard, 
for  example,  asphalt  mastic  on  top  of  wood  has  been  in  satisfactory 
use  for  many  years.    Johns  Hopkins  considered  this  material  for 
their  new  chemical  laboratories  but  abandoned  it  because  of  its 
viscous  properties,  substituting  granolithic  finish,  which  has  proved 
satisfactory. 

30  Tiles.    Tile  of  various  colors  is  an  excellent  material  for 
corridors,  lavatories,  and  even  for  laboratories,  but  is  too  expensive 
to  use  except  where  required  for  architectural  treatment.     There 
are  various  types  and  qualities  of  tile,  ranging  from  quarry  tile  to 
cork  and  rubber  tile.     All  of  them,  however,  are  expensive. 

31  Wood  Block.     Wood  block  may  be  suitable  in  certain  cases 
for  a  basement  floor  having  severe  usage.     In  the  University  of 
Cincinnati  wood  block  is  used  in  the  mechanical  and  electrical  testing 
laboratories  and  appears  to  be  satisfactory. 


SANFORD   E.    THOMPSON  395 

TESTS  AND   INVESTIGATIONS   OF   GRANOLITHIC   FLOORS 

32  The  material  used  most  largely  for  floor  surfaces  in  factory 
construction  and  also  to  a  considerable  extent  in  other  structures  is 
what  is  termed  a  granolithic  surface.     This,  as  generally  understood, 
is  a  layer  of  mortar  or  concrete  from  J/2-m-  to  2-in.  thick,  usually 
about  1  in.  on  top  of  the  concrete  slab  and  bonded  to  it.     Although 
granolithic  or  concrete  floors  are  so  widely  employed,  neither  the 
materials  nor  the  methods  of  construction  are  standardized  and 
scarcely  two  contractors  or  engineers  adopt  the  same  methods. 
Moreover,  the  materials  available  in  a  given  locality  largely  affect 
the  choice. 

33  In  order  to  compare  the  materials,  that  is,  the  aggregates, 
available  for  new  Technology,  and  to  determine  the  best  propor- 
tions and  methods  of  laying  these  materials,  a  series  of  sample  sur- 
faces were  laid  at  the  factory  of  the  Simplex  Wire  &  Cable  Company, 
in  Cambridge.    Also,  comparative  tests  were  made  with  similar 
materials  in  other  locations.     A  few  preliminary  laboratory  tests 
were  carried  through,  and  certain  tests  to  determine  the  best  method 
of  bonding  a  new  granolithic  surface  to  a  hardened  concrete  base. 
As  a  result  of  these  experiments,  the  following  recommendations  are 
made  for  the  granolithic  finish  of  floors  for  which  this  material  is 
to  be  used.     The  conclusions  apply  also  to  structures  in  general. 

34  Materials.    The  various  aggregates  used  in  the  tests  include 
three  kinds  of  sand  mixed  as  mortars  in  different  proportions,  and 
combinations  of  these  sands  with  samples  of  different  granites  and 
traps.     One  or  two  sections  were  also  laid  with  a  patented  compound. 

35  Careful  examination  and  comparisons  of  the  various  sections 
of  slab  with  reference  to  hardness  and  appearance  led  to  the  selection 
of  Plum  Island  sand,  which  should  be  specified  to  have  not  more 
than  10  per  cent  of  its  grains  pass  a  sieve  having  50  meshes  to  the 
linear  inch,  and  not  more  than  2  per  cent  pass  a  sieve  having  100 
meshes  to  the  linear  inch;    and  crushed  granite  of  a  size  which  has 
passed  the  J^-in.  screen  in  a  crusher  plant  and  been  caught  on  the 
3/16-in.  screen. 

36  As  a  result  of  this  selection,  a  slab  of  considerable  area  was 
laid  at  a  later  date  at  the  Simplex  factory  with  the  selected  materials 
and  proportions,  and  in  a  position  where  it  would  receive  rather  hard 
usage.     The  Simplex   Company   have    recently  advised  us   that 
they  consider  this  slab  the  best  piece  of  granolithic  that  has 
been  laid  in  the  factory. 


396        •  FLOOR    SURFACES   IN    FIREPROOF   BUILDINGS 

37  Proportions.     Different  proportions  of  the  materials  were 
employed  in  the  various  sample  sections,  each  of  which  was  about 
2  ft.  wide  by  3  ft.  long.     The  principal  proportions  tested  were  1 :2 
with  sand  alone;  1:1  J/£  with  sand  alone;  1:1:1J^  with  sand  and  fine 
crushed  stone;  1:1:1^  with  the  same  materials,  and  1:%:1J4-     As 
a  result  the  proportions  selected  as  best  are  one  part  cement  to  % 
parts  Plum  Island  sand  to  1J4  parts  crushed  granite. 

38  Method   of  Laying    Granolithic.     Instead  of   using   a   soft, 
flowing  mixture,  the  best  results  were  obtained  by  using  a  fairly 
stiff  mixture,  stiff  enough  to  be  rammed  in  place  by  a  square-faced 
rammer,  which  would  bring  the  mortar  readily  to  the  surface.     In 
this  way  the  surface  skin  is  thinner,  there  is  less  liability  to  dust,  and 
the  body  of  the  concrete,  which  is  of  a  better  quality  than  with  a 
wetter  mix,  is  reached  with  comparatively  little  wear,  so  that  the 
dusting  does  not  continue. 

39  Treatment  of  Surfaces.     Dusting  is  temporarily  overcome  by 
paint,  but  this  is  always  unsatisfactory  because  it  wears  off  under 
ordinary  travel,  and  if  the  concrete  is  not  of  the  best  quality  it  then 
begins  to  dust.     With  the  adoption  of  the  specifications  in  the 
Appendix  no  surface  material  should  be  needed. 

40  Grinding  Surfaces  of  Granolithic.     Objections  to  granolithic 
finish  are  dusting  of  the  surface,  the  dead  gray  color,  and  the  lia- 
bility of  local  defects.     Experiments  show  that  these  can  be  over- 
come by  grinding  the  surfaces  with  a  carborundum  machine.     This 
method  was  followed  on  a  section  of  slab  at  the  Simplex  Wire  & 
Cable  Company. 

41  The  general  plan  adopted  is  similar  to  that  used  with  terrazzo 
finish.     Instead,  however,  of  grinding  off  a  considerable  thickness 
and  thus  entailing  a  large  expense  per  square  foot,  only  a  very  thin 
layer  is  taken  off  so  as  to  show  the  grains  of  sand  and  the  pieces  of 
coarser  aggregate. 

42  With  this  treatment,  the  surface  is  of  a  varied  texture,  and 
shows  the  various  colored  grains,  and  permits  of  different  effects 
by  using  aggregates  of  different  colors.     While  the  effect  is  not  so 
conspicuous  as  the  terrazzo,  the  surface  is  of  a  quieter  tone,  and 
should  be  satisfactory  for  ordinary  corridors  and  halls.     The  grinding 
renders  the  surface  more  glossy  and  denser,  so  that  it  is  possible  to 
use  this  treatment  with  good  results  in  a  lavatory  or  other  places 
where  frequent  washing  and  cleaning  is  required.     To  produce  a 
more  ornamental  effect,  borders  or  patterns  of  tile  may  be  placed  in 
the  concrete. 


SANFORD   E.    THOMPSON  397 

43  Bond  of  Granolithic  to  Base  Concrete.     A  perfect  bond  be- 
tween the  granolithic  and  the  base  concrete  is  obtained  most  easily 
by  placing  the  granolithic  before  the  base  concrete  has  reached  its 
set.     Surfaces  thus  laid  are  liable  to  injury  from  the  workmen  who 
have  to  go  upon  them  before  they  have  hardened  thoroughly,  and 
occasionally  an  unexpected  shower  will  roughen  the  surface  in  such 
a  way  that  it  is  very  difficult  to  repair.     To  determine  the  best 
method  of  bonding,  one  which  would  give  thorough  assurance  of 
perfect  adhesion,  tests  were  made  and  then  tried  out  in  the  field  on  a 
large  concrete  building. 

44  Laboratory  tests  were  made  on  bonding  new  mortar  to  an  old 
concrete  surface,  using  various  methods  of  treatment  of  surface, 
ncluding  acid  treatment,   roughening,   and  no  surface  treatment 

whatever.  As  bonding  material,  neat  cement  was  used  in  dif- 
ferent conditions  of  plasticity,  also  certain  patented  compounds. 
As  a  result  of  these  tests  and  experience  in  the  field,  a  roughened 
surface  of  the  old  concrete,  with  neat  cement  paste  brushed  in,  is 
recommended  as  an  effective  method  to  produce  a  positive  bond. 

45  Specifications  for  bonding  are  given  in  the  Appendix.     It 
was  shown  in  the  tests  that  with  a  proper  neat  cement  bond  on  a 
roughened  surface  the  break  under  tension  was  frequently  through 
the  concrete  rather  than  at  the  joint. 

46  Preparing    Concrete   Base  for    other   Surface   Materials.     If 
some  other  material  than  granolithic  is  used  for  the  wearing  surface, 
the  base  concrete  must  be  left  in  a  condition  satisfactory  for  placing 
the  surface.     For  most  materials,  such  as  hardwood  finish,  com- 
position, asphalt,  and  similar  treatments,  the  surface  of  the  base 
must  be  brought  more  nearly  level  than  where  granolithic  is  used. 
This  can  be  accomplished  by  very  careful  screeding  of  the  surface, 
trowelling  of  rough  places,  and  filling  holes  made  by  footprints  before 
the  concrete  has  hardened.     An  allowance  of  1  cent  per  sq.  ft.  is 
made  in  the  cost  estimates  for  this  extra  treatment. 

47  For  linoleum,  a  real   granolithic  is  not  required,  but  the 
surface  must  be  level  and  true.     This  should  be  accomplished  by 
spreading  a  thin  layer  of  mortar  before  the  base  concrete  is  set,  but 
this  need  not  be  of  the  very  best  quality  of  granolithic  unless  with 
the  object  of  using  portions  of  the  floor  without  linoleum.     This 
thickness  of  the  mortar  may  be  Y^  in.  to  %  in.     This  should  be 
trowelled  at  the  proper  periods,  but  with  less  care  than  for  a  grano- 
lithic that  is  to  be  used  as  wearing  surface.     Some  form  of  cove  base 
around  the  walls  is  advantageous  to  use  with  the  linoleum. 


398  FLOOR   SURFACES   IN   FIREPROOF   BUILDINGS 

APPENDIX 

SPECIFICATIONS  FOR  LAYING   GRANOLITHIC   FINISH   ON  SET  CONCRETE 

48  Specifications  for  laying  granolithic  finish  on  set  concrete  are 
as  follows: 

a  Eoughen  surface  of  base  concrete  at  the  age  of  about  24  hours,  so 
as  to  remove  most  of  surface  scum. 

b  If  surfaces  have  not  been  thus  roughened,  pick  with  a  bushhammer 
to  remove  a  part  but  not  all  of  the  surface  skin. 

c  Spread  dilute  muriatic  acid  about  one  part  acid  to  four  parts  water 
over  the  surface,  allow  to  stand  for  a  few  minutes,  then  soak 
thoroughly  with  water,  and  wash  off  the  surface. 

d  Sweep  off  the  excess  water  on  the  surface  of  the  concrete  and  spread 
on  a  coating  about  %  in.  thick  of  neat  cement  paste,  and  broom 
it  well  into  the  concrete.  (Do  not  use  dry  cement  for  this.) 

e  Mix  the  granolithic  in  proportions  1  part  cement  to  %  parts  coarse 
sand,  like  Plum  Island,  to  1^  part  crushed  granite  screened  through 
a  %-in.  screen  and  caught  on  3/16-in.  dust  jacket. 

/  Make  the  consistency  of  granolithic  rather  stiff  so  that  the  mortar 
will  just  flush  to  the  surface. 

g  Have  the  screeds  laid  parallel  and  level  so  that  the  granolithic  can 
be  spread  even  with  straight-edge.  Eun  over  the  screeds.  See 
that  plenty  of  material  is  being  pushed  ahead  of  the  straight-edge 
at  all  times  so  as  to  avoid  pockets  in  the  surface. 

li    Earn  granolithic  with  light  square-faced  tamper. 

i    Float  granolithic  surface  as  soon  as  it  begins  to  stiffen. 

j  Trowel  granolithic  surface  hard  as  soon  as  the  proper  stage  has 
been  reached.  (If  surface  is  to  be  ground  do  not  give  surface 
this  final  trowelling.) 

fc  Cover  the  surfaces  of  the  granolithic  about  24  hours  after  laying, 
with  wet  burlap  or  similar  material  which  will  hold  water.  Wet 
material  each  day,  and  oftener  if  necessary,  for  a  period  of  14  days. 

GENERAL   REQUIREMENT 

49  Never  lay  concrete  finish  in  cold  weather  unless  a  uniform 
temperature  can  be  maintained  by  artificial  heat,  as  the  cold  pre- 
vents the  surface  of  the  granolithic  from  hardening  satisfactorily. 
In  laying  floors  where  water  is  to  be  used,  care  should  be  exercised 
to  provide  the  required  slope  for  cleaning  and  drainage.     This  is 
especially  necessary  in  such  places  as  chemical  laboratories. 

GRINDING    GRANOLITHIC    SURFACES 

50  Specifications  for  granolithic  grinding  surfaces  are  as  follows : 
a    Lay  the  granolithic  as  described  in  Appendix  No.  1,  but  omit  the 

final  trowelling. 


SANFOKD   E.    THOMPSON  399 

&  Bub  the  granolithic  surface  by  hand  with  carborundum  block  at  the 
age  of  about  24  hours  after  placing.  Eub  lightly  and  take  off 
only  the  top  scum  of  the  cement  and  remove  any  surface  irregu- 
larities. 

c  Grind  the  surfaces  with  a  floor  polishing  machine  at  the  age  of 
about  7  days  (time  varies  with  weather  and  temperature).  Use 
about  60-80  grit  with  water  and  do  not  use  any  sand  unless  it  is 
found  necessary.  This  grinding  should  take  off  the  top  film  of  the 
surface  and  cut  into  the  sand  grains  enough  to  expose  them  and 
to  leave  the  surface  smooth  but  not  shiny. 

d    Eub  wet  cement  paste  into  any  pinholes. 

DISCUSSION 

In  presenting  the  paper  THE  AUTHOR  stated  that  good  grano- 
lithic floors  were  being  built  which  would  stand  very  severe  traffic 
and  dust  only  to  a  very  small  degree.  The  five  principal  require- 
ments are,  materials,  proportions,  bonding,  methods  of  laying,  and 
treatment  of  surface.  Use  coarse  material  with  the  cement,  avoid- 
ing fine  sand  or  stone  with  fine  particles  because  this  rises  to  the 
surface  in  trowelling.  Use  a  comparatively  dry  mix  that  will  re- 
quire a  slight  tamping.  There  are  certain  compounds  on  the  market 
that  will  prevent  dusting,  but  if  the  right  materials  and  workmanship 
are  employed,  so  little  dusting  will  occur  that  it  will  not  be  objec- 
tionable for  ordinary  uses. 

For  durability  it  is  best  to  lay  the  floor  surface  along  with  the 
base  concrete.  This  is  often  impracticable  and  tests  have  proven 
that  a  good  bond  can  be  obtained  on  old  concrete  with  the  proper 
treatment.  Special  attention  is  called  to  the  specifications  given 
at  the  close  of  the  paper  and  to  the  note  with  reference  to  laying 
granolithic  in  cold  weather. 

Ross  F.  TucKER1  (written) .  So  much  difficulty  exists  in  securing 
a  good  wearing  surface  for  granolithic  that  hardwood  is  preferred  for 
all  purposes,  particularly  where  operatives  have  to  be  on  their  feet. 

L.  C.  WASON2  (written).  In  regard  to  costs,  my  figures  for 
granolithic  construction  would  in  each  case  be  2  cents  less  than 
those  quoted  by  the  author.  For  hardwood  floors,  there  is  a  dif- 
ference of  3%  cents  per  sq.  ft.  between  2  in.  face  by  1^  in.  thick 
and  3^  in.  face  by  %  in.  thick,  in  both  cases  the  material  costing 

'Consulting  Engineer,  35  W.  32d  St.,  New  York. 

2Pres.  and  Engr.,  Aberthaw  Constr.  Co.,  8  Beacon  St.,  Boston,  Mass. 


400  FLOOR   SURFACES    IN    FIREPROOF   BUILDINGS 

the  same  per  thousand.  Magnesium  composition  is  also  laid  at  a 
third  less  than  quoted. 

Lameness  and  fatigue,  which  factory  operatives  thought  were 
caused  by  the  hardness  of  granolithic  floors,  are  due  to  the  fact  that 
such  floors  are  better  conductors  of  heat.  This  has  been  overcome 
where  floors  are  cold  by  wearing  heavy  shoes. 

Nalecod,  another  material  composed  of  asbestos,  portland  cement 
and  sand,  is  giving  better  results  than  screed  for  wood  floors. 

For  a  granolithic  floor  no  particles  should  be  used  smaller  than 
those  passing  a  No.  30  sieve,  and  hard  rock  which  will  withstand 
abrasion  should  be  used,  without  any  sand,  the  proportion  being  one 
to  two.  In  bonding  to  old  surfaces,  a  thin  top  i.e.,  %  in.  or  1  in., 
is  more  likely  to  come  loose  than  a  thicker  one. 

Commenting  on  paragraph  48,  a  multiple  pick  is  cheaper  and 
requires  a  less  experienced  workman  than  a  bush  hammer. 

Dilute  muriatic  acid  is  unsafe  unless  the  concrete  is  dense,  other- 
wise it  is  likely  to  soften  it. 

The  mixture  should  not  be  limited  to  granite,  as  traps  and  gravel 
give  good  results.  A  stiff  mortar  gives  best  results,  although  a  dif- 
ferent consistency  should  be  used,  depending  on  whether  the  base 
is  fully  set. 

G.  S.  WALKER.  There  is  almost  certain  to  be  trouble  with  grano- 
lithic if  the  base  is  allowed  to  set  and  an  attempt  afterward  made  to 
bond  the  surface  to  it.  This  is  due  to  the  shrinkage  rate  being  dif- 
ferent. They  should  always  be  laid  together. 

WALTER  S.  TIMMIS.  There  is  a  very  serious  defect  in  wood  floors 
in  fireproof  buildings,  that  of  springiness.  This  was  more  apparent 
in  the  earlier  buildings  where  floors  were  laid  directly  on  the  arches, 
but  even  in  recent  buildings  it  occurs,  owing  to  lack  of  care  in  bring- 
ing the  cinder  fill  to  the  top  of  the  screed.  Dry  rotting  of  screed 
also  often  takes  place,  especially  when  the  floor  is  laid  before  the 
cement  is  dry.  On  granolithic  floors,  the  difficulty  in  getting  a 
smooth  surface  and  no  dusting  is  due  to  the  trowelling  not  being 
done  at  the  psychological  moment. 

G.  P.  HEMSTREET  (written).  I  desire  to  call  attention  to  another 
form  of  asphalt  floor  for  fireproof  buildings,  streets,  piers,  ware- 
houses, etc.,  used  for  many  years,  viz.,  asphalt  blocks  composed  of 
hard  crushed  stone  and  about  7  per  cent  asphaltic  cement  formed 
under  hydraulic  pressure  of  various  sizes  and  forms.  These  are  laid 


DISCUSSION  401 

in  cement  mortar  with  joints  grouted.  The  surface  is  smooth,  re- 
silient, non-slipping,  dustless,  sanitary  and  not  easily  marred.  This 
material  can  be  taken  up  whenever  desired  and  readily  replaced. 
The  cost  is  $1.50  to  $2.50  per  square  yard. 

THE  AUTHOR,  in  closing,  recognizes  the  iorce  of  Mr.  Wason's 
requirement  that  the  aggregates  should  be  practically  free  from 
grains  finer  than  a  No.  30  sieve.  Unless  a  sand  consisting  of  very 
coarse  grains,  like  Plum  Island  sand,  is  available,  he  agrees  that  it 
is  proper  to  use  an  aggregate  with  no  sand  but  with  particles  graded 
from  %  inch  down  to,  say,  a  No.  30  sieve. 

Regarding  Mr.  Walker's  criticism  on  bonding  new  granolithic 
surfaces  to  old  concrete,  the  best  answer  is  that  it  has  been  done 
with  good  results  by  the  methods  described. 


THE  AMERICAN  SOCIETY  OF  MECHANICAL 
ENGINEERS 

REPORT 

OF  THE  COMMITTEE 
TO  FORMULATE  STANDARD  SPECIFICATIONS 

FOR  THE 

CONSTRUCTION  OF  STEAM  BOILERS  AND  OTHER 

PRESSURE  VESSELS  AND  FOR  THEIR 

CARE  IN  SERVICE 


KNOWN    AS 

THE  BOILER  CODE  COMMITTEE 


RULES  FOR  THE 

CONSTRUCTION  OF  STATIONARY  BOILERS  AND 
FOR  ALLOWABLE  WORKING  PRESSURES 

Edition  of  1914  with  Index 

Copyright,    1915,   by 
THE    AMERICAN    SOCIETY    OF    MECHANICAL    ENGINEERS 


To  THE  COUNCIL  OF  THE  AMERICAN  SOCIETY  OF 
MECHANICAL  ENGINEERS 

Gentlemen:  Your  Committee  appointed  September  15th,  1911  to 
"Formulate  Standard  .Specifications  for  the  Construction  of  Steam 
Boilers  and  Other  Pressure  \7essels  and  for  Care  of  .Same  in  Service'"'* 
respectfully  submits  its  final  report  on  Eules  for  the  construction  and 
allowable  working  pressures  of  stationary  boilers,  which  forms  a  por- 
tion of  the  task  assigned  to  it. 

The  primary  object  of  these  Eulcs  is  to  secure  safe  boilers.  The 
interests  of  boiler  users  and  manufacturers  have  been  carefully  con- 
sidered and  the  requirements  made  such  that  they  will  not  entail 
undue  hardship  by  departing  too  widely  from  present  practice. 

Your  Committee  recommends  that  you  appoint  a  permanent  com- 
mittee to  make  such  revisions  as  may  be  found  desirable  in  these  Eules. 
and  to 'modify  them  as  the  state  of  the  art  advances,  and  that  such 
committee  should  hold  meetings  at  least  once  in  two  years  at  which 
all  interested  parties  may  be  heard. 

Yours  truly, 


JOHN  A.  STEVENS,  Chairman 
WM.  H.  BOEHM 
EOLLA  C.  CARPENTER 
KICHARD  HAMMOND 
CHAS.  L.  HUSTON 
EDWARD  F.  MILLER 
H.  C.  MEINHOLTZ* 
E.  I).  MEIER* 


COMMITTEE 


Deceased* 


Submitted  to  the  Council  of  THE  AMERICAN  SOCIETY  OP  MECHANICAL  ENGINEERS,  Feb- 
ruary 13,  1915. 


Your  Committee  secured  the  assistance  of  the  following  Engi- 
neers as  an  Advisory  Committee,  representing  various  phases  of  the 
design,  installation  and  operation  of  boilers  and  the  Eules  were  un- 
animously approved  by  them.  • 

F.  II.  CLARK,  Kailroad  Sub-Committee,  The  American  Society  of  Mechanical 
Engineers. 

F.  W.  DEAN,  Consulting  Engineers. 

THOS.  E.  DURBAN,  Boiler  Manufacturers'  Association,  Uniform  Specifica- 
tions Committee,  for  all  types  of  boilers. 

CARL  FERRARI,  National  Tubular  Boiler  Manufacturers'  Association. 

ELBERT  C.  FISHER,  Scotch  marine  and  other  types  of  boilers. 

ARTHUR  M.  GREENE,  JR.,  Engineering  Education. 

CHAS.  E.  GORTON,  Steel  heating  boilers. 

A.  L.  HUMPHREY,  Eailroad  Sub-Committee,  The  American  Society  of  Me- 
chanical Engineers. 

D.  S.  JACOBUS,  Water-tube  boilers. 

S.  F.  JETER,  Boiler  insurance. 

WM.  F.  KIESEL,  JR.,  Eailroad  Sub-Committee,  The  American  Society  of  Me- 
chanical Engineers. 

W.  F.  MACGREGOR,  National  Association  of  Thresher  Manufacturers. 

M.  F.  MOORE,  Steel  heating  boilers. 

I.  E.  MOULTROP,  Boiler  users. 

EICHARD  D.  EEED,  National  Boiler  &  Eadiator  Manufacturers'  Association. 

H.  G.  STOTT,  Boiler  users. 

H.  H.  VAUGHAN,  Eailroad  Sub-Committee,  The  American  Society  of  Me 
chanical  Engineers. 

C.  W.  OBEET,  Secretary  to  Committee. 


CONTENTS 

Part  I.     New  Installations  PAGES 

Section  1.     Power  Boilers 7-80 

Section  2.    -Heating  Boilers 81-87 

Part  II.     Existing  Installations 89-93 

Appendix 95-114 

Index             .                                                                                                          .  115-147 


RULES  FOR  THE 

CONSTRUCTION  OF  STATIONARY  BOILERS 

AND  FOR  ALLOWABLE  WORKING 

PRESSURES 


These  Rules  do  not  apply  to  boilers  which  are  subject  to  federal 
inspection  and  control,  including  marine  boilers,  boilers  of  steam  loco- 
motive and  other  self-propelled  railroad  apparatus. 


The  Rules  are  divided  into  two  parts: 

.,,,,.         f Section  I,  Power  Boilers. 
PART  I  applies  to  new  installations.  J  „ 

\  Section  II,  Heating  Boilers. 

PART  II  applies  to  existing  installations. 


PART  I     NEW  INSTALLATIONS 

SECTION  I 
POWER  BOILERS 

SELECTION  OF  MATERIALS 


1  Specifications  are  given  in  these  Rules  for  the  important  ma- 
terials used  in  the  construction  of  boilers,  and  where  given,  the  ma- 
terials shall  conform  thereto. 

2  Steel  plates  for  any  part  of  a  boiler  when  exposed  to  the  fire 
or  products  of  combustion,  arid  under  pressure,  shall  be  of  firebox 
quality  as  designated  in  the  Specifications  for  Boiler  Plate  Steel. 

3  Steel  plates  for  any  part  of  a  boiler,  where  firebox  quality  is 
not  specified,  when  under  pressure,  shall  be  of  firebox  or  flange  quality 
as  designated  in  the  Specifications  for  Boiler  Plate  .Steel. 

4  Braces  when  welded,  shall  be  of  wrought-iron  of  the  quality 
designated  in  the  Specifications  for  Refined  Wrought-iron  Bars. 

5  Manhole  and  handhole  covers  and  other  parts  subjected  to  pres- 
sure and  braces  and  lugs,  when  made  of  steel  plate,  shall  be  of  firebox 
or  flange  quality   as  designated  in  the  Specifications  for  Boiler  Plate 
Steel. 

6  Steel  bars  for  braces  and  for  other  boiler  parts,  except  as  other- 
wise specified  herein,  shall  be  of  the  quality  designated  in  the  Specifi- 
cations for  Steel  Bars. 

7  Staybolts  shall  be  of  iron  or  steel  of  the  quality  designated  in 
the  Specifications  for  Staybolt  Iron  or  in  the  Specifications  for  Stay- 
bolt  Steel. 


3  REPORT  OF  BOILER  CODE  COMMITTEE,   AM.SOC.M.E. 

8  Kivets  shall  be  of  steel  or  iron  of  the  quality  designated  in  the 
Specifications  for  Boiler  Eivet  Steel  or  in  the  Specifications  for  Boiler 
Rivet  Iron. 

9  Cross  pipes  connecting  the  steam  and  water  drums  of  water- 
tube  boilers,  headers  and  cross  boxes  and  all  pressure  parts  of  the  boiler 
proper  over  2-in.  pipe  size,  or  equivalent  cross-sectional  area,  shall  be 
of  wrought  steel,  or  cast  steel  of  Class  B  grade,  as  designated  in  the 
Specifications  for  Steel  Castings,  when  the  maximum  allowable  work- 
ing pressure  exceeds  160  Ib.  per  sq.  in. 

10  Mud  drums  of  boilers  used  for  other  than  heating  purposes 
shall  be  of  wrought  steel,  or  cast  steel  of  Class  B  grade,  as  designated 
in  the  'Specifications  for  Steel  Castings. 

11  Pressure  parts  of  superheaters,  separately  fired  or  attached  to 
stationary  boilers,  unless  of  the  locomotive  type,  shall  be  of  wrought 
steel,  or  cast  steel  of  Class  B  grade,  as  designated  in  the  Specifications 
for  Steel  Castings. 

12  Cast  iron  shall  not  be  used  for  boiler  and  superheater  mount- 
ings, such  as  nozzles,  connecting  pipes,  fittings,  valves  and  their  bon- 
nets, for  steam  temperatures  of  over  450  deg.  fahr. 

13  Water-leg  and  door-frame  rings  of  vertical  fire-tube  boilers 
36  in.  or  over  in  diameter,  and  of  locomotive  and  other  type  boilers, 
shall  be  of  wrought  iron  or  steel,  or  cast  steel  of  Class  B  grade,  as 
designated  in  the  Specifications  for  Steel  Castings.    The  0  G  or  other 
flanged  construction  may  be  used  as  a  substitute  in  any  case. 


ULTIMATE  STRENGTH  OF  MATERIAL  USED  IN  COMPUTING  JOINTS 

14  Tensile  Strength  of  Steel  Plate.     The  tensile  strength  used 
in  the  computations  for  steel  plates  shall  be  that  stamped  on  the  plates 
as  herein  provided,  which  is  the  minimum  of  the  stipulated  range,  or 
55,000  Ibs.  per  sq.  in.  for  all  steel  plates,  except  for  special  grades 
having  a  lower  tensile  strength. 

15  Crushing  Strength  of  Steel  Plate.     The  resistance  to  crush- 
ing of  steel  plate  shall  be  taken  at  9-5,000  Ib.  per  sq.  in.  of  cross-sec- 
tional area. 

16  Strength  of  Eivets  in  Shear.     In  computing  the  ultimate 


NEW  INSTALLATIONS,  PART  I,  SECTION  I,  POWER  BOILERS  9 

strength  of  rivets  in  shear,  the  following  values  in  pounds  per  square 
inch  of  the  cross-sectional  area  of  the  rivet  shank  shall  be  used : 

Iron  rivets  in  single  shear 38,000 

Iron  rivets  in  double  shear 76,000 

Steel  rivets  in  single  shear 44,000 

Steel  rivets  in  double  .shear 88,000 

The  cross-sectional  area  used  in  the  computations  shall  be  that  of 
the  rivet  shank  after  driving. 

MINIMUM  THICKNESSES  OF  PLATES  AND  TUBES 

1 7  Thickness  of  Plates.     The  minimum  thickness  of  any  boiler 
plate  under  pressure  shall  be  14  in. 

18  The  minimum  thicknesses  of  shell  plates,  and  dome  plates 
after  flanging,  shall  be  as  follows: 

WHEN  THE  DIAMETER  OF  SHELL  is 

36  In.  or  Under       Over  36  In.  to  54  In.       Over  54  In.  to  72  In.       Over  72  In. 

14  in.  tfc  in.  %  in.  %  in. 

19  The  minimum  thicknesses  of  butt  straps  shall  be  as  given  in 
Table  1. 

TABLE  1     MINIMUM  THICKNESSES  OF  BUTT  STRAPS 


Thickness  of 

Minimum  Thickness 

Thickness  of 

Minimum  Thickness 

Shell  Plates, 

of  Butt  Straps, 

Shell  Plates, 

of  Butt  Straps, 

In. 

In. 

In. 

In. 

H 

M 

H 

A 

A 

K 

A 

A 

A 

Yi 

% 

H 

H 

H 

y* 

H 

H 

A 

% 

K 

H 

A 

i 

m 

A 

y* 

1H 

X 

H 

H 

lit 

% 

1A 

A 

20     The  minimum  thicknesses  of  tube  sheets  for  horizontal  return 
tubular  boilers,  shall  be  as  follows: 


WHEN  THE  DIAMETER  OF  TUBE  SHEET  is 

42  In.  or  Under       Over  42  In.  to  54  In.       Over  54  In.  to  72  In.       Over  72  In, 
%  in.  iV  in.  in.  in. 


10  REPORT  OF  BOILER  CODE  COMMITTEE,  AM.SOC.M.E. 

21  Tubes  for  Water-Tube  Boilers.  The  minimum  thicknesses 
of  tubes  used  in  water-tube  boilers  measured  by  Birmingham  wire 
gage,  for  maximum  allowable  working  pressures  not  exceeding  165  Ib. 
per  sq.  in.,  shall  be  as  follows: 

Diameters  less  than  3  in No.  12  B.W.G. 

Diameter  3  in.  or  over,  but  less  than  4  in ." No.  1 1  B.W.G. 

Diameter  4  in.  or  over,  but  less  than  5  in No.  10  B.W.G. 

Diameter  5  in No.     9  B.W.G. 

V 

The  above  thicknesses  shall  be  increased  for  maximum  allowable 
working  pressures  higher  than  1G5  Ib.  per  sq.  in.  as  follows: 

Over  165  Ib.  but  not  exceeding  235  Ib 1  gage 

Over  235  Ib.  but  not  exceeding  285  Ib 2  gages 

Over  285  Ib.  but  not  exceeding  400  Ib 3  gages 

Tubes  over  4-in.  diameter  shall  not  be  used  for  maximum  allowable 
working  pressures  above  285  Ib.  per  sq.  in. 

2-2  Tubes  for  Fire-Tube  Boilers.  The  minimum  thicknesses  .of 
tubes  used  in  fire  tube  boilers  measured  by  Birmingham  wire  gage,  for 
maximum  allowable  working  pressures  not  exceeding  175  Ib.  per  sq. 
in.,  shall  be  as  follows : 

Diameters  less  than  2^  in No.  13  B.W.G. 

Diameter  2y2  in.  or  over,  but  less  than  3^  in No.  12  B.W.G. 

Diameter  3^4  in.  or  over,  but  less  than  4  in No.  11  B.W.G. 

Diameter  4      in.  or  over,  but  less  than  5  hi No.  10  B.W.G. 

Diameter  5      in No.     9  B.W.G. 

For  higher  maximum  allowable  working  pressures  than  given  above 
the  thicknesses  shall  be  increased  one  gage. 


NEW  INSTALLATIONS,   PART  I,  SECTION  I,   POWER  BOILERS  11 

SPECIFICATIONS  FOR  BOILER  PLATE   STEEL 

THESE    SPECIFICATIONS1    ARE    SIMILAR    TO    THOSE    OF    THE    AMER- 
I  'AN  SOCIETY  FOR  TESTING  MATERIALS,  SERIAL  DESIGNATION  A    3O-14. 

23  Grades.     These  specifications  cover  two  grades  of  steel  for 
1  oilers,  namely :   FLANGE  and  FIREBOX. 

I     MANUFACTURE 

24  Process.     The  steel  shall  be  made  by  the  open-hearth  process. 

II     CHEMICAL  PROPERTIES  AND  TESTS 

25  Chemical  Composition.     The  steel  shall  conform  to  the  fol- 
lowing requirements  as  to  chemical  composition: 


FLANGE  FIREBOX 

Carbon Plates  %  in.  thick  and  under.  .  0.12 — 0.25  percent 

Plates  over  %  in.  thick ,.0.12—0.30  per  cent 

Manganese 0.30—0.60  per  cent  0.30—0.50  per  cent 

I  Acid Not  over  0.05  per  cent  Not  over  0.04    per  cent 

US  |  Basic Not  over  0.04  per  cent  Not  over  0.035  per  cent 

Sulphur Not  over  0.05  per  cent  Not  over  0.04    per  cent 

Copper Not  over  O.C5    per  cent 

26  Ladle  Analyses.     An  analysis  shall  be  made  by  the  manu- 
facturer from  a  test  ingot  taken  during  the  pouring  of  each  melt,  a 
cop^-  of  which  shall  be  given  to  the  purchaser  or  his  representative. 
This  analysis  shall  conform  to  the  requirements  specified  in  Par.  25. 

27  Check  Analyses.     Analyses  may  be  made  by  the  purchaser 
from  a  broken  tension  test  specimen  representing  each  plate  as  rolled, 
which  shall  conform  to  the  requirements  specified  in  Par.  25. 


''Approved  and  recommended  in  its  modified  form,  October  9,  1914,  by  the 
Association  of  American  Steel  Manufacturers,  the  American  Boiler  Manu- 
facturers' Association,  the  National  Tubular  Boiler  Manufacturers'  Associa- 
tion, the  National  Association  of  Thresher  Manufacturers  and  the  representa- 
tives present  of  leading  Water  Tube  Boiler  Manufacturers,  with  whom  the 
Boiler  Code  Committee  was  in  conference  on  September  16,  1914,  and  by  whom 
further  modifications  were  afterwards  offered. 


12  REPORT  OP  BOILER  CODE  COMMITTEE,   AM.SOC.M.E. 

ITT     PHYSICAL  PROPERTIES  AND  TESTS 

28     Tension  Tests,     a     The  material  shall  conform  to  the  follow- 
ing requirements  as  to  tensile  properties : 


FLANGE  FIREBOX 

Tensile  strength,  Ib.  per  sq.  in 55,000—65,000  55,000—63,000 

Yield  point,  ruin.,  Ib.  per  sq.  in 0.5  tens.  str.  0.5  tens.  str. 

Elongation  in  8-in.,  min.,  per  cent  (See  Par.  29)  1,500,000  1,500,000 


Tens.  str.  Tens.  str. 

b  If  desired  steel  of  lower  tensile  strength  than  the  above  may  be 
used  in  an  entire  boiler,  or  part  thereof,  the  desired  tensile  limits  to 
be  specified,  having  a  range  of  10,000  Ib.  per  sq.  in.  for  flange  or  8000 
Ib.  per  sq.  in.  for  firebox,  the  steel  to  conform  in  all  respects  to  the 
other  corresponding  requirements  herein  specified,  and  to  be  stamped 
with  the  minimum  tensile  strength  of  the  stipulated  range. 

c  The  yield  point  shall  be  determined  by  the  drop  of  the  beam 
of  the  testing  machine. 

29  Modifications  in  Elongation,     a     For  material  over  %  in.  in 
thickness,   a   deduction  of   0.5   from  the   percentages   of   elongation 
specified  in  Par.  28a,  shall  be  made  for  each  increase  of  %  in.  in 
thickness  above  %  in.,  to  a  minimum  of  20  per  cent. 

b  For  material  %  in.  or  under  in  thickness,  the  elongation  shall 
be  measured  on  a  gage  length  of  21  times  the  thickness  of  the  specimen. 

30  Bend  Tests,     a     Cold-lend  Tests— The  test  specimen  shall 
bend  cold  through  180  deg.  without  cracking  on  the  outside  of  the 
bent  portion,  as  follows :   For  material  1  in.  or  ynder  in  thickness,  flat 
on  itself;  and  for  material  over  1  in.  in  thickness,  around  a  pin  the 
diameter  of  which  is  equal  to  the  thickness  of  the  specimen. 

I  Quench-lend  Tests — The  test  specimen,  when  heated  to  a  light 
cherry  red  as  seen  in  the  dark  (not  less  than  1200  deg.  fahr.),  and 
quenched  at  once  in  water  the  temperature  of  which  is  between  80  deg. 
and  90  deg.  fahr.,  shall  bend  through  180  deg.  without  cracking  on  the 
outside  of  the  bent  portion,  as  follows :  For  material  1  in.  or  under  in 
thickness,  flat  on  itself;  and  for  material  over  1  in.  in  thickness, 
around  a  pin  the  diameter  of  which  is  equal  to  the  thickness  of  the 
specimen. 

31  Homogeneity  Tests.     For  firebox  steel,  a  sample  taken  from 
a  broken  tension  test  specimen  shall  not  show  any  single  seam  cr 
cavity  more  than  %  in.  long,  in  either  of  the  three  fractures  obtained 
in  the  test  for  homogeneity,  which  shall  be  made  as  follows : 


NEW  INSTALLATIONS,  PART  I,  SECTION  I,  POWER  TOILERS  13 

The  specimen  shall  be  either  nicked  with  a  chisel  or  grooved  on 
a  machine,  transversely,  about  1/16  in.  deep,  in  three  places  about 
2  in.  apart.  The  first  groove  shall  be  made  2  in.  from  the  square  end ; 
each  succeeding,  groove  shall  be  made  on  the  opposite  side  from  the 
preceding  one.  The  specimen  shall  then  be  firmly  held  in  a  vise,  with 
the  first  groove  about  !/4  in-  above  the  jaws,  and  the  projecting  end 
broken  off  by  light  blows  of  a  hammer,  the  bending  being  away  from 
the  groove.  The  specimen  shall  be  broken  at  the  other  two  grooves  in 
the  same  manner.  The  object  of  this  test  is  to  open  and  render  visible 
to  the  eye  any  seams  due  to  failure  to  weld  or  to  interposed  foreign 
matter,  or  any  cavities  due  to  gas  bubbles  in  the  ingot.  One  side  of 
each  fracture  shall  be  examined  ard  the  length  of  the  seams  and 
cavities  determined,  a  pocket  lens  being  used  if  necessary. 

32  Test  Specimens.  Tension  and  bend  test  specimens  shall  be 
taken  from  the  finished  rolled  material.  They  shall  be  of  the  full 


4 

7*             -wl     »>P       !«-• 

Parallel  Sect 

nof  less  tha 

nd"~' 

I         ^  IT- 

A 
i        i        i        .       .  1, 

t:1 
•                •                •        1                                      -        °J  

r-i-i     3 

f 

^                   ^ 

E—  -^3 

.-  //? 

/f 

J 

FIG.  1     STANDARD  FORM  OF  TEST  SPECIMEN  REQUIRED  FOR  ALL  TENSION  TESTS 

OF  PLATE  MATERIAL 

thickness  of  material  as  rolled,  and  shall  be  machined  to  the  form  and 
dimensions  shown  in  Fig.  1 ;  except  that  bend  test  specimens  may  be 
machined  with  both  edges  parallel. 

33  Number  of  Tests,  a  One  tension,  one  cold-bend,  and  one 
quench-bend  test  shall  be  made  from  each  plate  as  rolled. 

b  If  any  test  specimen  shows  defective  machining  or  develops 
flaws,  it  may  be  discarded  and  another  specimen  substituted. 

c  If  the  percentage  of  elongation  of  any  tension  test  specimen  is 
less  than  that  specified  in  Pars.  28  and  29,  and  any  part  of  the  fracture 
is  outside  the  middle  third  of  the  gaged  length,  as  indicated  by  the 
scribe  scratches  marked  on  the  specimen  before  testing,  a  retest  shall 
be  allowed. 

IV    PERMISSIBLE  VARIATION  IN  GAGE 

34     Permissible  Variation.     The  thickness  of  each  plate  shall  not 
vary  under  the  gage  specified  more  than  0.01  in.     The  overweight 


14  REPORT  OF  BOILER  CODE  COMMITTEE,  AM.SOC.M.E. 

limits  are  considered  a  matter  of  contract  between  the  steel  manu- 
facturer and  the  boiler  builder. 

Y     FINISH 

35  Finish.     The  finished  material  shall  be  free  from  injurious 
defects  and  shall  have  a  workmanlike  finish. 

VI     MARKING 

36  Marking,     a     Each  shell  plate  shall  be  legibly  stamped  by 
the  manufacturer  with  the  melt  or  slab  number,,   name  of  manu- 
facturer, grade  and  the  minimum  tensile  strength  of  the  stipulated 
range  as  specified  in  Par.  28,  in  three  places,  two  of  which  shall  be 
located  at  diagonal  corners  about  12  in.  from  the  edge  and  one  about 
the  center  of  the  plate,  or  at  a  point  selected  and  designated  by  the 
purchaser  so  that  the  stamp  shall  be  plainly  visible  when  the  boiler  is 
completed. 

&  Each  head  shall  be  legibly  stamped  by  the  manufacturer  in 
two  places,  about  12  in.  from  the  edge,  with  the  melt  or  slab  number, 
name  of  manufacturer,  grade,  and  the  minimum  tensile  strength 
of  the  stipulated  range  as  specified  in  Par.  28,  in  such  manner  that 
the  stamp  is  plainly  visible  when  the  boiler  is  completed. 

c  Each  butt  strap  shall  be  legibly  stamped  by  the  manufacturer 
in  two  places  on  the  center  line  about  12  in.  from  the  ends  with  the 
melt  or  slab  number,  name  of  manufacturer,  grade,  and  the  minimum 
tensile  strength  of  the  stipulated  range  as  specified  in  Par.  ,28. 

d  The  melt  or  slab  number  shall  be  legibly  stamped  on  each  test 
specimen. 

VII     INSPECTION  AND  REJECTION 

37  Inspection.     The  inspector  representing  the  purchaser  shall 
have  free  eutrj,  at  all  times  while  work  on  the  contract  of  the  pur- 
chaser is  being  performed,  to  all  parts  of  the  manufacturer's  works 
which  concern  the  manufacture  of  the  material  ordered.     The  manu- 
facturer shall  afford  the  inspector,  free  of  cost,  all  reasonable  facilities 
to  satisfy  him  that  the  material  is  being  furnished  in  accordance  with 
these  specifications.    All  tests  (except  check  analyses)  and  inspection 
shall  be  made  at  the  place  of  manufacture  prior  to  shipment,  unless 
otherwise  specified,  and  shall  be  so  conducted  as  not  to  interfere  un- 
necessarily with  the  operation  of  the  works. 


NEW  INSTALLATIONS,  PART  I,  SECTION  I,  POWER  BOILERS  15 

38  Rejection,     a     Unless  otherwise  specified,  any  rejection  based 
on  tests  made  in  accordance  with  Par.  27  shall  be  reported  within  five 
working  days  from  the  receipt  of  samples. 

b  Material  which  shows  injurious  defects  subsequent  to  its  ac- 
ceptance at  the  manufacturer's  works  will  be  rejected,  and  the  manu- 
facturer shall  be  notified. 

39  Rehearing.     Samples  tested  in  accordance  with  Par.  ,27,  which 
represent  rejected  material,  shall  be  preserved  for  two  weeks  from  the 
date  of  the  test  report.    In  case  of  dissatisfaction  with  the  results  of 
the  tests,  the  manufacturer  may  make  claim  for  a  rehearing  within 
that  time. 


SPECIFICATIONS  FOR  BOILER  RIVET  STEEL 

THESE  SPECIFICATIONS  ARE  SUBSTANTIALLY  THE  SAME  AS  THOSE 
OF  THE  AMERICAN  SOCIETY  FOR  TESTING  MATERIALS,  SERIAL  DESIG- 
NATION A  31-14. 

A     REQUIREMENTS  FOR  ROLLED  BARS 

I     MANUFACTURE 

40  Process.     The  steel  shall  be  made  by  the  open-hearth  process. 

II     CHEMICAL  PROPERTIES  AND  TESTS 

41  Chemical  Composition.     The  steel  shall  conform  to  the  fol- 
lowing requirements  as  to  chemical  composition : 

Manganese 0.30-0.50     per  cent 

Phosphorus    not  over  0.04     per  cent 

Sulphur    not  over  0.045  per  cent 

42  Ladle  Analyses.     An  analysis  to  determine  the  percentages 
of  carbon,  manganese,  phosphorus  and  sulphur  shall  be  made  by  the 
manufacturer  from  a  test  ingot  taken  during  the  pouring  of  each  melt, 
a  copy  of  which  shall  be  given  to  the  purchaser  or  his  representative. 
This  analysis  shall  conform  to  the  requirements  specified  in  Par.  41. 

43  Check  Analyses.     Analyses  may  be  made  by  the  purchaser 
from  finished  bars,  representing  each  melt,  which  shall  conform  to  the 
requirements  specified  in  Par.  41. 


16  REPORT  OP  BOILER  CODE  COMMITTEE,  AM.SOC.M.E. 

Ill     PHYSICAL  PROPERTIES  AND  TESTS 

44  Tension  Tests,     a     The  bars  shall  conform  to  the  following 
requirements  as  to  tensile  properties: 

Tensile  strength,  Ib.  per  sq.  in 45,000-55,000 

Yield  point,  inin.,  Ib.  per  sq.  in 0.5  tens.  str. 

Elongation  in  8  in.,  min.,  per  cent 1,500,000 

but  need  not  exceed  30  per  cent.  Tens.  str. 

b  The  yield  point  shall  be  determined  by  the  drop  of  the  beam  of 
the  testing  machine. 

45  Bend  Tests,     a     Cold-bend  Tests — The  test  specimen  shall 
bend  cold  through  180  deg.  flat  on  itself  without  cracking  on  the  out- 
side of  the  bent  portion. 

b  Quench-bend  Tests — The  test  specimen,  when  heated  to  a  light 
cherry  red  as  seen  in  the  dark  (not  less  than  1200  deg.  fahr.),  and 
quenched  at  once  in  water  the  temperature  of  which  is  between  80  deg. 
and  90  deg.  fahr.,  shall  bend  through  180  deg.  flat  on  itself  without 
cracking  on  the  outside  of  the  bent  portion. 

46  Test  Specimens.     Tension  and  bend  test  specimens  shall  be 
of  the  full-size  section  of  bars  as  rolled. 

47  Number  of  Tests,     a     Two  tension,  two  cold-bend,  and  two 
quench-bend  tests  shall  be  made  from  each  melt,  each  of  which  shall 
conform  to  the  requirements  specified. 

b  If  any  test  specimen  develops  flaws,  it  may  be  discarded  and 
another  specimen  substituted. 

c  If  the  percentage  of  elongation  of  any  tension  test  specimen 
is  less  than  that  specified  in  Par.  44  and  any  part  of  the  fracture  is 
outside  the  middle  third  of  the  gaged  length,  as  indicated  by  scribe 
scratches  marked  on  the  specimen  before  testing,  a  retest  shall  be 
allowed. 

48  Permissible  Variations  in  Gage.     The  gage  of  each  bar  shall 
not  vary  more  than  0.01  in.  from  that  specified. 

V    WORKMANSHIP  AND  FINISH 

49  Workmanship.     The   finished  bars  shall  be  circular  within 
0.01  in: 

50  Finish.     The  finished  bars  shall  be  free  from  injurious  de- 
fects and  shall  have  a  workmanlike  finish. 


NEW  INSTALLATIONS,  PART  I,  SECTION  I,  POWER  BOILERS  17 

VI     MARKING 

51  Marking.     Rivet  bars  shall,  when  loaded  for  shipment,  be 
properly  separated  and  marked  with  the  name  or  brand  of  the  manu- 
facturer and  the  melt  number  for  identification.     The  melt  number 
shall  be  legibly  marked  on  each  test  specimen. 

VII     INSPECTION  AND  REJECTION 

52  Inspection.     The  inspector  representing  the  purchaser  shall 
have  free  entry,  at  all  times  while  work  011  the  contract  of  the  pur- 
chaser is  being  performed,  to  all  parts  of  the  manufacturer's  works 
which  concern  the  manufacture  of  the  bars  ordered.      The  manu- 
facturer shall  afford  the  inspector,  free  of  cost,  all  reasonable  facilities 
to  satisfy  him  that  the  bars  are  being  furnished  in  accordance  with 
these  specifications.    All  tests  (except  check  analyses)  and  inspection 
shall  be  made  at  the  place  of  manufacture  prior  to  shipment,  unless 
otherwise  specified,  and  shall  be  so  conducted  as  not  to  interfere  un- 
necessarily with  the  operation  of  the  works. 

53  Rejection,     a     Unless  otherwise  specified,  any  rejection  based 
on  tests  made  in  accordance  with  Par.  43  shall  be  reported  within  five 
working  days  from  the  receipt  of  samples. 

b  Bars  which  show  injurious  defects  subsequent  to  their  ac- 
ceptance at  the  manufacturer's  works  will  be  rejected,  and  the  manu- 
facturer shall  be  notified. 

54  Rehearing.     .Samples  tested  in  accordance  with  Par.  43,  which 
represent  rejected  bars,  shall  be  preserved  for  two  weeks  from  the 
date  of  the  test  report.    In  case  of  dissatisfaction  with  the  results  of 
the  tests,  the  manufacturer  may  make  claim  for  a  rehearing  within 
that  time. 

B    REQUIREMENTS  FOR  RIVETS 

I     PHYSICAL  PROPERTIES  AND  TESTS 

55  Tension  Tests.     The  rivets,  when  tested,  shall  conform  to  the 
requirements  as  to  tensile  properties  specified  in  Par.  44,  except  that 
the  elongation  shall  be  measured  on  a  gaged  length  not  less  than  four 
times  the  diameter  of  the  rivet. 

56  Bend  Tests.     The  rivet  shank  shall  bend  cold  through  180 
deg.  flat  on  itself,  as  shown  in  Fig.  2,  without  cracking  on  the  outside 
of  the  bent  portion. 


IS 


REPORT  OF  BOILER  CODE  COMMITTEE,   AM.SOC.M.E. 


57  'Flattening  Tests.     The  rivet  head  shall  flatten,  while  hot,  to 
a  diameter  2l/2  times  the  diameter  of  the  shank,  as  shown  in  Fig.  3, 
without  cracking  at  the  edges. 

58  Number  of  Tests,    a     When  specified,  one  tension  test  shall 
be  made  from  each  size  in  each  lot  of  rivets  offered  for  inspection. 

1)  Three  bend  and  three  flattening  tests  shall  be  made  from  each 
size  in  each  lot  of  rivets  offered  for  inspection,  each  of  which  shall  con- 
form to  the  requirements  specified. 

II    WORKMANSHIP  AND  FINISH 

59  Workmanship.     The  rivets  shall  be  true  to  form,  concentric, 
and  shall  be  made  in  a  workmanlike  manner. 

60  Finish.     The  finished  rivets  shall  -be  free  from  injurious  de- 
fects. 


FIG.  2     THE  BEND 
TEST  FOR  EIVETS 


FIG.  3    THE  FLAT- 
TENING TEST  FOB 
EIVETS 


III     INSPECTION  AND  REJECTION 

61  Inspection.  The  inspector  representing  the  purchaser  shall 
have  free  entry,  at  all  times  while  work  on  the  contract  of  the  pur- 
chaser is  being  performed,  to  all  parts  of  the  manufacturer's  works 
which  concern  the  manufacture  of  the  rivets  ordered.  The  manu- 
facturer shall  afford  the  inspector,  free  of  cost,  all  reasonable  facilities 
to  satisfy  him  that  the  rivets  are  being  furnished  in  accordance  with 
these  specifications.  All  tests  and  inspection  shall  be  made  at  the 
place  of  manufacture  prior  to  shipment,  unless  otherwise  specified, 
and  shall  be  so  conducted  as  not  to  interfere  unnecessarily  with  the 
operation  of  the  works. 

62  Rejection.  "Rivets  which  show  injurious  defects  subsequent 
to  their  acceptance  at  the  manufacturer's  works  will  be  'rejected,  and, 
the  manufacturer  shall  be  notified. 


NEW  INSTALLATIONS,  TART  I,  SECTION  I,  POWER  BOILERS  19 

SPECIFICATIONS  FOR  STAYBOLT  STEEL 

REQUIREMENTS  FOR  ROLLED  BARS 

63  Steel    for   staybolts   shall   conform   to   the   requirements   for 
Boiler  Rivet  Steel  specified  in  Pars.  40  to  6.2,  except  that  the  tensile 
properties  shall  be  as  follows : 

Tensile  strength,  Ib.  per  sq.  in 50,000-60,000 

Yield  point,  min.,  Ib.  per  sq.  in 0.5  tens.  str. 

1,500,000 
Elongation  in  8  in.,  min.,  per  cent — 

Tens.  str. 

Also  with  the  exception  that  the  permissible  variations  in  gage  shall 
be  as  follows : 

Permissible  Variations  in  Gage.  The  bars  shall  be  truly  round 
within  0.01  in.  and  shall  not  vary  more  than  0.005  in.  above,  or  more 
than  0.01  in.  below  the  specified  size. 

SPECIFICATIONS  FOR  STEEL  BARS 

THESE  SPECIFICATIONS  ARE  ABSTRACTED  FROM  THOSE  FOR  STEEL 
FOR  BRIDGES  OF  THE  AMERICAN  SOCIETY  FOR  TESTING  MATERIALS, 
SERIAL  DESIGNATION  A  7-14. 

I     MANUFACTURE 

64  Process.     The  steel  shall  be  made  by  the  open-hearth  process. 

II     CHEMICAL  PROPERTIES  AND  TESTS 

65  Chemical  Composition.     The  steel  shall  conform  to  the  fol- 
lowing requirements  as  to  chemical  composition : 

(  Acid    not  over  0.06  per  cent 

Phosphorus  |  Bagic    not  oyer  0>04  per  cent 

Sulphur    not  over  0.05  per  cent 

66  Ladle  Analysis.     An  analysis  to  determine  the  percentages  of 
carbon,  manganese,  phosphorus  and  sulphur  shall  be  made  by  the 
manufacturer  from  a  test  ingot  taken  during  the  pouring  of  each 
melt,  a  copy  of  which  shall  be  given  to  the  purchaser  or  his  representa- 
tive.    This  analysis  shall  conform  to  the  requirements  specified  in 
Par.  65. 


20  REPORT  OF  BOILER  CODE  COMMITTEE.    AM.SOC.M.E. 

Ill     PHYSICAL  PROPERTIES  AND  TESTS 

67  Tension  Tests,     a     The  material  shall  conform  to  the  follow- 
ing requirements  as  to  tensile  properties : 

Tensile  strength,  Ib.  per  sq.  in 55,000-65,000 

Yield  point,  min.,  per  sq.  in : 0.5  tens.  str. 

1,500,000    . 
Elongation  in  8  in.,  min.,  per  cent* • 

Tens.  str. 

Elongation  in  2  in.,  min.,  per  cent 22 

*See  Par.  68. 

I)  The  yield  point  shall  be  determined  by  the  drop  of  the  beam  of 
the  testing  machine. 

68  Modifications  in  Elongation,     a     For  bars  over   %   in.   in 
thickness  or  diameter  a  deduction  of  1  from  the  percentage  of  elonga- 
tion in  8  in.  specified  in  Par.  67,  shall  be  made  for  each  increase  of  % 
in.  in  thickness  or  diameter  above  %  in.,  to  a  minimum  of  18  per  cent. 

b  For  bars  under  5/16  in.  in  thickness  or  diameter  a  deduction 
of  2.5  from  the  percentage  of  elongation  in  8  in.  specified  in  Par.  67, 
shall  be  made  for  each  decrease  of  1/16  in.  in  thickness  or  diameter 
below  5/16  in. 

69  Bend  Tests,     a     The  test  specimen  shall  bend  cold  through 
180  deg.  without  cracking  on  the  outside  of  the  bent  portion,  as  fol- 
lows:   For  material  %  in.  or  under  in  thickness  or  diameter  flat  on 
itself;  for  material  over  %  in.  to  and  including  l1^  in.  in  thickness  or 
diameter  around  a  pin  the  diameter  of  which  is  equal  to  the  thickness 
or  diameter  of  the  specimen;  and  for  material  over  l1/^  in.  in  thickness 
or  diameter  around  a  pin  the  diameter  of  which  is  equal  to  twice  the 
thickness  or  diameter  of  the  specimen. 

&  The  test  specimen  for  bars  over  iy2  in.  in  thickness  or  diameter 
when  prepared  as  specified  in  Par.  70,  shall  bend  cold  through  ISO 
deg.  around  a  1-in.  pin  without  cracking  on  the  outside  of  the  bent 
portion. 

70  Test  Specimens,     a     Tension  and  bend  test  specimens  except 
as  specified  in  h,  shall  be  of  the  full  thickness  of  material  as  rolled. 
They  may  i)e  machined  to  the  form  and  dimensions  shown  in  Fig.  1, 
or  may  have  both  edges  parallel. 

&  Tension  test  specimens  for  bars  over  1%  in.  in  thickness  or 
diameter  may  be  of  the  form  and  dimensions  shown  in  Fig.  4.  Bend 


NEW  INSTALLATIONS,  PART  I,  SECTION  I,  POWER  BOILERS  21 

test  specimens  may  be  1  by  Vii  ijl-  in  section.  The  axis  of  the  specimen 
shall  be  located  at  any  point  midway  between  the  center  and  surface 
and  shall  be  parallel  to  the  axis  of  the  bar. 

71  Number  of  Tests,     a     One  tension  and  one  bend  test  shall  be 
made  from  each  melt;  except  that  if  material  from  one  melt  differs 
%  in.  or  more  in  thickness,  one  tension  and  one  bend  test  shall  be 
made  from  both  the  thickest  and  the  thinnest  material  rolled. 

b  If  any  test  specimen  shows  defective  machining  or  develops 
flaws,  it  may  be  discarded  and  another  specimen  substituted. 

c  If  the  percentage  of  elongation  of  any  tension  test  specimen  is 
less  than  that  specified  in  Par.  67,  and  any  part  of  the  fracture  is 
more  than  %  in.  from  the  center  of  the  gage  length  of  a  2-in.  specimen 
or  is  outside  the  middle  third  of  the  gage  length  of  an  8-in.  specimen, 
as  indicated  by  scribe  scratches  marked  on  the  specimen  before  testing, 
a  retest  shall  be  allowed. 

IV     PERMISSIBLE  VARIATIONS  IN  GAGE 

72  Permissible  Variation.     The  thickness  or  cross-section  of  each 
piece  of  steel  shall  not  vary  under  that  specified  more  than  2.5  per 
cent.     (NOTE:    Overweight  variation  is  a  matter  of  contract  between 
the  steel  manufacturer  and  boiler  builder.) 

V     FINISH 

73  Finish.     The  finished  material  shall  be  free  from  injurious 
defects  and  shall  have  a  workmanlike  finish. 

VI     MARKING 

74  Marking.     Bars  shall,  when  loaded  for  shipment,  be  properly 
separated  and  marked  with  the  name  or  brand  of  the  manufacturer 
and  melt  number  for  identification.    The  melt  number  shall  be  legibly 
marked  on  each  test  specimen. 

VII     INSPECTION  AND  REJECTION' 

75  Inspection.     The  inspector  representing  the  purchaser  shall 
have  free  entry,  at  all  times  while  work  on  the  contract  of  the  pur- 
chaser is  being  performed,  to  all  parts  of  the  manufacturer's  works 


REPORT  OF  BOILER  CODE  COMMITTEE,  AM.SOC.M.E. 

which  concern  the  manufacture  of  the  material  ordered.  The  manu- 
facturer shall  afford  the  inspector,  free  of  cost,  all  reasonahle  facilities 
to  satisfy  him  that  the  material  is  heing  furnished  in  accordance  with 
these  specifications.  All  tests  and  inspection  shall  be  made  at  the  place 
of  manufacture  prior  to  shipment,  unless  otherwise  specified,  and  shall 
be  so  conducted  as  not  to  interfere  unnecessarily  with  the  operation  of 
the  works. 

76  Rejection.  Material  which  shows  injurious  defects  subsequent 
to  its  acceptance  at  the  manufacturer's  works  will  be  rejected,  and  the 
manufacturer  shall  be  notified. 


SPECIFICATIONS  FOR  STEEL  CASTINGS 

THESE  SPECIFICATIONS  ARE  ABSTRACTED  FROM  THOSE  FOR  STEEL 
CASTINGS  OF  THE  AMERICAN  SOCIETY  FOR  TESTING  MATERIALS, 
SERIAL  DESIGNATION  A  27-14. 

77  Classes.     These  specifications  cover  two  classes  of  castings, 
namely : 

Class  A,  ordinary  castings  for  which  no  physical  requirements 

are  specified. 
Class  B,  castings  for  which  physical  requirements  are  specified. 

These  are  of  three  grades:    hard,  medium,  and  soft. 

78  Patterns,     a     Patterns  shall  be  made  so  that  sufficient  finish 
is  allowed  to  provide  for  all  variations  in  shrinkage. 

I)  Patterns  shall  be  painted  three  colors  to  represent  metal,  cores, 
and  finished  surfaces.  It  is  recommended  that  core  prints  shall  be 
painted  black  and  finished  surfaces  red. 

79  Basis  of  Purchase.     The  purchaser  shall  indicate  his  intention 
to  substitute  the  test  to  destruction  specified  in  Par.  87,  for  the  tension 
and  bend  tests,  and  shall  designate  the  patterns  from  which  castings 
for  this  test  shall  be  made. 

I     MANUFACTURE 

80  Process.     The  steel  may  be  made  by  the  open-hearth,  crucible, 
or  any  other  process  approved  by  the  purchaser. 

81  Heat  Treatment,     a     Class  A  castings  need  not  be  annealed 
unless  so  specified. 

I  Class  B  castings  shall  be  allowed  to  become  cold.  They  shall 
then  be  uniformly  reheated  to  the  proper  temperature  to  refine  the 


NEW  INSTALLATIONS,  PART  I,  SECTION  I,  POWER  BOILERS  23 

grain  (a  group  thus  reheated  being  known  as  an  "annealing  charge"), 
and  allowed  to  cool  uniformly  and  slowly.  If,  in  the  opinion  of  the 
purchaser  or  his  representative,  a  casting  is  not  properly  annealed,  he 
may  at  his  option  require  the  casting  to  be  re-annealed. 


II     CHEMICAL  PROPERTIES  AND  TESTS 

82  Chemical  Composition.     The  castings  shall  conform  to  the 
following  requirements  as  to  chemical  composition : 

Class  A  Class  B 

Carbon not  over  0.30  per  cent  

Phosphorus  .  . , not  over  0.06  per  cent  not  over  0.05  per  cent 

Sulphur not  over  0.05  per  cent 

83  Ladle  Analyses.     An  analysis  to  determine  the  percentages  of 
carbon,  manganese,  phosphorus  and  sulphur  shall  be  made  by  the  man- 
ufacturer from  a  test  ingot  taken  during  the  pouring  of  each  melt,  a 
copy  of  which  shall  be  given  to  the  purchaser  or  his  representative. 
This  analysis  shall  conform  to  the  requirements  specified  in  Par.  82. 
Drillings  for  analysis  shall  be  taken  not  less  than  %  in.  beneath  the 
surface  of  the  test  ingot. 

84  Check  Analyses,     a     Analyses  of  Class  A   castings  may  be 
made  by  the  purchaser,  in  which  case  an  excess  of  20  per  cent  above  the 
requirement  as  to  phosphorus  specified  in  Par.  82,  shall  be  allowed. 
Drillings  for  analysis  shall  be  taken  not  less  than  %  in  beneath  the 
surface. 

1)  Analyses  of  Class  B  castings  may  be  made  by  the  purchaser 
from  a  broken  tension  or  bend  test  specimen,  in  which  case  an  excess 
of  20  per  cent  above  the  requirements  as  to  phosphorus  and  sulphur 
specified  in  Par.  82,  shall  be  allowed.  Drillings  for  analysis  shall  be 
taken  not  less  than  V\  in.  beneath  the  surface. 


Ill     PHYSICAL  PROPERTIES  AND  TESTS 
(For  Class  B  Castings  only.) 

85     Tension  Tests,     a     The  castings  shall  conform  to  the  follow- 
ing minimum  requirements  as  to  tensile  properties: 


24  REPORT  OF  BOILER  CODE  COMMITTEE,  AM.SOC.M.E. 

Hard  Medium  Soft 

Tensile  strength,  Ib.  per  sq.  in 80,000  70,000  60,000 

Yield  point,  Ib.  per  sq.  in 36,000  31,500  27,000 

Elongation  in  2  in.,  per  cent 15  18  22 

Eeduction  of  area,  per  cent 20  25  30 

&  The  yield  point  shall  be  determined  by  the  drop  of  the  beam 
of  the  testing  machine. 

8'6  Bend  Tests,  a  The  test  specimen  for  soft  castings  shall  bend 
cold  through  120  deg.,  and  for  medium  castings  through  90  deg., 
around  a  1-in.  pin,  without  cracking  on  the  outside  of  the  bent  portion. 

I)     Hard  castings  shall  not  be  subject  to  bend  test  requirements. 

87  Alternative  Tests  to  Destruction.     In  the  case  of  small  or  un- 
important castings,  a  test  to  destruction  on  three  castings  from  a  lot 
may  be  substituted  for  the  tension  and  bend  tests.    This  test  shall  show 
the  material  to  be  ductile,  free  from  injurious  defects,  and  suitable 
for  the  purpose  intended.    A  lot  shall  consist  of  all  castings  from  one 
melt,  in  the  same  annealing  charge. 

88  Test  Specimens,     a     Sufficient  test  bars,  from  which  the  test 
specimens  required  in  Par.  89,  may  be  selected,  shall  be  attached  to 
castings  weighing  500  Ib.  or  over,  when  the  design  of  the  castings  will 
permit.    If  the  castings  weigh  less  than  500  Ib.,  or  are  of  such  a  design 
that  test  bars  cannot  be  attached,  two  test  bars  shall  be  cast  to  represent 
each  melt;  or  the  quality  of  the  castings  shall  be  determined  by  tests 
to  destruction  as  specified  in  Par.  87.    All  test  bars  shall  be  annealed 
with  the  castings  they  represent. 

&  The  manufacturer  and  purchaser  shall  agree  whether  test  bars 
can  be  attached  to  castings,  on  the  location  of  the  bars  on  the  castings, 
on  the  castings  to  which  bars  are  to  be  attached,  and  on  the  method 
of  casting  unattached  bars. 

c  Tension  test  specimens  shall  be  of  the  form  and  dimensions 
shown  in  Fig.  4.  Bend  test  specimens  shall  be  machined  to  1  by  % 
in.  in  section  with  corners  rounded  to  a  radius  not  over  1/16  in. 

89  Number  of  Tests,     a     One  tension  and  one  bend  test  shall  be 
made  from  each  annealing  charge.     If  more  than  one  melt  is  repre- 
sented in  an  annealing  charge,  one  tension  and  one  bend  test  shall  be 
made  from  each  melt. 

I  If  any  test  specimen  shows  defective  machining  or  develops 
flaws,  it  may  be  discarded;  in  which  case  the  manufacturer  and  the 
purchaser  or  his  representative  shall  agree  upon  the  selection  of  an- 
other specimen  in  its  stead. 


NEW  INSTALLATIONS,   TART  I,   SECTION  I,   POWER  BOILERS  25 

(••  If  the  percentage  of  elongation  of  any  tension  test  specimen  is 
less  than  that  specified  in  Par.  85,  and  any  part  of  the  fracture  is 
more  than  %  in-  from  the  center  of  the  gaged  length,  as  indicated  by 
scribe  scratches  marked  on  the  specimen  before  testing,  a  retest  shall 
be  allowed. 

IV    WORKMANSHIP  AND  FINISH 

90  Workmanship.     The  castings  shall  substantially  conform  to 
the  sizes  and  shapes  of  the  patterns,  and  shall  be  made  in  a  workman- 
like manner. 

91  Finish,     a     The  castings  shall  be  free  from  injurious  defects. 
I)     Minor  defects  which  do  not  impair  the  strength  of  the  castings 

may,  witli  the  approval  of  the  purchaser  or  his  representative,  be 


FIG.  4     STANDARD  FORM  OF  TEST  SPECIMEN  REQUIRED  FOR  ALL  TENSION  TESTS 
OF  STEEL  CASTING  MATERIAL 

welded  by  an  approved  process.  The  defects  shall  first  be  cleaned  out 
to  solid  metal;  and  after  welding,  the  castings  shall  be  annealed,  if 
specified  by  the  purchaser  or  his  representative. 

c  The  castings  offered  for  inspection  shall  not  be  painted  or 
covered  with  any  substance  that  will  hide  defects,  nor  rusted  to  such 
an  extent  as  to  hide  defects. 


V    INSPECTION  AND  REJECTION 

92  Inspection.  The  inspector  representing  the  purchaser  shall 
have  free  entry,  at  all  times  while  work  on  the  contract  of  the  pur- 
chaser is  being  performed,  to  all  parts  of  the  manufacturer's  works 
which  concern  the  manufacture  of  the  castings  ordered.  The  manu- 
facturer shall  afford  the  inspector,  free  of  cost,  all  reasonable  facilities 
to  satisfy  him  that  the  castings  are  being  furnished  in  accordance  with 


26  REPORT  OF  BOILER  CODE  COMMITTEE,   AM.SOC.M.E. 

these  specifications.  All  tests  (except  check  analyses)  and  inspection 
shall  be  made  at  the  place  of  manufacture  prior  to  shipment,  unless 
otherwise  specified,  and  shall  he  so  conducted  as  not  to  interfere  un- 
necessarily with  the  operation  of  the  works. 

93  Rejection,  a  Unless  otherwise  specified,  any  rejection  hased 
on  tests  made  in  accordance  with  Par.  84,  shall  be  reported  within 
five  working  days  from  the  receipt  of  samples. 

I  Castings  which  show  injurious  defects  subsequent  to  their  ac- 
ceptance at  the  manufacturer's  works  will  be  rejected,  and  the  manu- 
facturer shall  be  notified. 

94-  Rehearing.  Samples  tested  in  accordance  with  Par.  84, 
which  represent  rejected  castings,  shall  be  preserved  for  two  weeks 
from  the  date  of  the  test  report.  In  case  of  dissatisfaction  with  the 
results  of  the  tests,  the  manufacturer  may  make  claim  for  a  rehearing 
within  that  time. 


SPECIFICATIONS  FOR  GRAY  IRON  CASTINGS 

THESE  SPECIFICATIONS  ARE  IDENTICAL  WITH  THOSE  OF  THE 
AMERICAN  SOCIETY  FOR  TESTING  MATERIALS,  SERIAL  DESIGNATION 
A  48-05. 

95  Process  of  Manufacture.     Unless  furnace  iron  is  specified,  all 
gray  castings  are  understood  to  be  made  by  the  cupola  process. 

96  Chemical  Properties.     The  sulphur  contents  to  be  as  follows : 

Light  castings    not  over  0.08  per  cent 

Medium  castings    not  over  0.10  per  cent 

Heavy  Castings    not  over  0.12  per  cent 

97  Classification.     In  dividing  castings  into  light,  medium  and 
heavy  classes,  the  following  standards  have  been  adopted : 

98  Castings  having  any  section  less  than  i/>  in.  thick  shall  be 
known  as  light  castings. 

99  Castings  in  which  no  section  is  less  than  2  in.  thick  shall  be 
known  as  heavy  castings. 

100  Medium  castings  are  those  not  included  in  the  above  classifi- 
cation. 


NEW  INSTALLATIONS,  TART  I,  SECTION  I,  POWER  BOILERS        27 
PHYSICAL  PROPERTIES  AND  TESTS 

101     Transverse  Test.     The  minimum  breaking  strength  of  the 
"Arbitration  Bar"  under  transverse  load  shall  be  not  under: 


Light  castings  .  . 
Medium  castings 
Heavy  castings  . 


2500  Ibs. 
2900  Ibs. 
3300  Ibs. 


In  no  ease  shall  the  deflection  be  under  0.10  in. 

103     Tensile  Test.     Where  specified,  this  shall  not  run  less  than : 

Light  castings 18,000  Ib.  per  sq.  in. 

Medium  castings 21,000  11).  per  sq.  in. 

Heavy  castings   24,000  Ib.  per  sq.  in. 


Stcf.  Thread 


X~M 


U 


FIG.  5     STANDARD  FORM  OF  TEST  SPECIMEN  KEQUIRED  FOR  TENSION  TESTS 
GRAY-IRON  CASTING  MATERIAL 


103  Arbitration  Bar.     The  quality  of  the  iron  going  into  castings 
under  specification  shall  be  determined  by  means  of  the  "Arbitration 
Bar."    This  is  a  bar  P/4  in.  in  diameter  and  15  in.  long.     It  shall  be 
prepared  as  stated  further  on  and  tested  transversely.     The  tensile 
test  is  not  recommended,  but  in  case  it  is  called  for,  the  bar  as  shown 
in  Fig.  5,  and  turned  up  from  any  of  the  broken  pieces  of  the  trans- 
verse test  shall  be  used.     The  expense  of  the  tensile  test  shall  fall  on 
the  purchaser. 

104  Number  of  Test  Bars.     Two  sets  of  two  bars  shall  be  cast 
from  each  heat,  one  set  from  the  first  and  the  other  set  from  the  last 
iron  going  into  the  castings.    Where  the  heat  exceeds  twenty  tons,  an 
additional  set  of  two  bars  shall  be  cast  for  each  twenty  tons  or  fraction 
thereof  above  this  amount.     In  case  of  a  change  of  mixture  during 
the  heat,  one  set  of  two  bars  shall  also  be  cast  for  every  mixture  other 


28 


REPORT  OF  BOILER  CODE  COMMITTEE,   AM.SOf.M.E. 


than  the  regular  one.  Each  set  of  two  bars  is  to  go  into  a  single  mold. 
The  bars  shall  not  be  rumbled  or  otherwise  treated,  being  simply 
brushed  off  before  testing. 

105     Method  of  Testing.     The  transverse  test  shall  be  made  on  all 
the  bars  cast,  with  supports  12  in.  apart,  load  applied  at  the  middle, 


PATTERN 


c\j 


-•x 


IO    Pipe  Cope 


1 


I 


FIG.  6     DETAILS  OF  PATTERN  AND  MOLD  REQUIRED  FOR  ARBITRATION  BARS  IN 
TESTING  GRAY-!RON  CASTING  MATERIAL 

and  the  deflection  at  rupture  noted.  One  bar  of  every  two  of  each  set 
made  must  fulfill  the  requirements  to  permit  acceptance  of  the  cast- 
ings represented. 

106  Mold  for  Test  Bar.  The  mold  for  the  bars  is  shown  in  Fig. 
6.  The  bottom  of  the  bar  is  1/16  in.  smaller  in  diameter  than  the 
top,  to  allow  for  draft  and  for  the  strain  of  pouring.  The  pattern 
shall  not  be  rapped  before  withdrawing.  The  flask  is  to  be  rammed  up 


NEW  INSTALLATIONS,  TART  I,  SECTION  I,  POWER  BOILERS  29 

with  green  molding  sand,  a  little  damper  than  usual,  well  mixed  and 
put  through  a  Xo.  8  sieve,  with  a  mixture  of  one  to  twelve  bituminous 
facing.  The  mold  shall  be  rammed  evenly  and  fairly  hard,  thoroughly 
dried  and  not  cast  until  it  is  cold.  The  test  bar  shall  not  be  removed 
from  the  mold  until  cold  enough  to  be  handled. 

107  Speed  of  Testing.     The  rate  of  application  of  the  load  shall 
be  from  20  to  40  seconds  for  a  deflection  of  0.10  in. 

108  Samples  for  Analysis.     Borings  from  the  broken  pieces  of 
the  "Arbitration  Bar"  shall  be  used  for  the  sulphur  determinations. 
One  determination  for  each  mold  made  shall  be  required.    In  case  of 
dispute,  the  standards  of  the  American   Foundrymen's  Association 
shall  be  used  for  comparison. 

109  Finish.     Castings  shall  be  true  to  pattern,  free  from  cracks, 
flaws  and  excessive  shrinkage.     In  other  respects  they  shall  conform 
to  whatever  points  may  be  specially  agreed  upon. 

110  Inspection.     The  inspector  shall  have  reasonable  facilities 
afforded  him  by -the  manufacturer  to  satisfy  him  that  the  finished 
material  is  furnished  in  accordance  with  these  specifications.     All 
tests  and  inspections  shall,  as  far  as  possible,  be  made  at  the  place  of 
manufacture  prior  to  shipment. 


SPECIFICATIONS    FOR   MALLEABLE    CASTINGS 

THESE  SPECIFICATIONS  ARE  IDENTICAL  WITH  THOSE  OF  THE 
AMERICAN  SOCIETY  FOR  TESTING  MATERIALS,  SERIAL  DESIGNATION 
A  47-04. 

111  Process  of  Manufacture.     Malleable  iron  castings  may  be 
made  by  the  open-hearth,  air  furnace,  or  cupola  process.    Cupola  iron, 
however,  is  not  recommended  for  heavy  nor  for  important  castings. 

112  Chemical  Properties.     Castings  for  which  physical  require- 
ments are  specified  shall  not  contain  over  0.06  sulphur  nor  -over  0.225 
phosphorus. 

PHYSICAL  PROPERTIES  AND  TESTS 

113  Standard  Test  Bar.     This  bar  shall  be  1  in.  sq.  and  14  in. 
long,  without  chills  and  with  ends  left  perfectly  free  in  the  mold. 
Three  shall  be  cast  in  one  mold,  heavy  risers  insuring  sound  bars. 
Where  the  full  heat  goe3  into  castings  which  are  subject  to  specifica- 


30  RETORT  OF  BOILER  CODE  COMMITTEE,  AM.SOC.M.E. 

tion,  one  mold  shall  be  poured  two  minutes  after  tapping  into  the  first 
ladle,  and  another  mold  from  the  last  iron  of  the  heat.  Molds  shall  be 
suitably  stamped  to  insure  identification  of  the  bars,  the  bars  being 
annealed  with  the  castings.  Where  only  a  partial  heat  is  required  for 
the  work  in  hand,  one  mold  should  be  cast  from  the  first  ladle  used 
and  another  after  the  required  iron  has  been  tapped. 

a  Of  the  three  test  bars  from  the  two  molds  required  for  each 
heat,  one  shall  be  tested  for  tensile  strength  and  elongation,  the  other 
for  transverse  strength  and  deflection.  The  other  remaining  bar  is 
reserved  for  either  the  transverse  or  tensile  test,  in  case  of  the  failure 
of  the  two  other  bars  to  come  up  to  requirements.  The  halves  of  the 
bars  broken  transversely  may  also  be  used  for  the  tensile  test. 

b  Failure  to  reach  the  required  limit  for  the  tensile  strength 
with  elongation,  as  also  the  transverse  strength  with  deflection,  on 
the  part  of  at  least  one  test,  shall  reject  the  castings  from  that  heat. 

114  Tensile  Test.     The  tensile  strength  of  a  standard  test  bar 
for   castings  under   specification   shall   not  be   less   than   40,000   Ib. 
per  sq.  in.     The  elongation  measured  in  2  in.  shall  not  be  less  than 
%y2  per  cent. 

115  Transverse  Test.     The  transverse  strength  of  a  standard  test 
bar,  on  supports  12  in.  apart,  pressure  being  applied  at  the  center,  shall 
not  be  less  than  3000  Ib.,  deflection  being  at  least  %  in. 

116  Test  Lugs.     Castings  of  special  design  or  of  special  impor- 
tance may  be  provided  with  suitable  test  lugs  at  the  option  of  the 
inspector.    At  least  one  of  these  lugs  shall  be  left  on  the  casting  for 
his  inspection  upon  his  request  therefor. 

117  Annealing.     Malleable  castings  shall  neither  be  "over"  nor 
"under"  annealed.     They  must  have  received  their  full  heat  in  the 
oven  at  least  sixty  hours  after  reaching  that  temperature. 

118  The  "saggers"  shall  not  be  dumped  until  the  contents  shall 
at  least  be  "black  hot." 

119  FinisJi.     Castings    stiall    be    true    to    pattern,    free    from 
blemishes,  scale  or  shrinkage  cracks.    A  variation  of  1/16  in.  per  foot 
shall  be  permissible.      Founders   shall   not  be   held   responsible   for 
defects  due  to  irregular  cross  sections  and  unevenly  distributed  metal. 

120  Inspection.     The  inspector  representing  the  purchaser  shall 
have  all  reasonable  facilities  given  him  by  the  founder  to  satisfy  him 
that   the   finished   material   is   furnished   in   accordance   with   these 
specifications.    All  tests  and  inspections  shall  be  made  prior  to  ship- 
ment, 


NEW  INSTALLATIONS,  PART  I,  SECTION  I,  POWER  BOILERS  31 

SPECIFICATIONS  FOR  BOILER  RIVET  IRON 

THESE  REQUIREMENTS  ARE  AN  ADAPTATION,  WITH  SLIGHT  MODI- 
FICATIONS IN  THE  PHYSICAL  PROPERTIES  AND  TESTS,  OF  THE  SPECI- 
FICATIONS FOR  ENGINE  BOLT  IRON  OF  THE  AMERICAN  SOCIETY  FOR 
TESTING  MATERIALS. 

A     REQUIREMENTS  FOR  ROLLED  BARS 

I     MANUFACTURE 

121  Process.  .The  iron  shall  he  made  wholly  from  puddled  iron 
or  knobbled  charcoal  iron,  and  shall  he  free  from  any  admixture  of 
iron  scrap  or  steel. 

12.2  Iron  Scrap.  This  term  applies  only  to  foreign  or  bought 
scrap  and  does  not  include  local  mill  products  free  from  foreign  or 
bought  scrap. 

IT     PHYSICAL  PROPERTIES  AND  TESTS 

1.23  Tension  Tests,  a  The  iron  shall  conform  to  the  following 
requirements  as  to  tensile  properties: 

Tensile  strength,  Ib.  per  sq.  in 48,000-52,000 

Yield  point,  min.,  Ib.  per  sq.  in 0.6  tens.  str. 

Elongation  in  8  in.,  min.,  per  cent 28 

Reduction  of  area,  min.,  per  cent 45 

1}  The  yield  point  shall  be  determined  by  the  drop  of  the  beam 
of  the  testing  machine.  The  speed  of  the  cross-head  of  the  machine 
shall  not  exceed  1%  in.  Per  minute. 

124  Bend  Tests,  a  Cold-lend  Tests — The  test  specimen  shall 
bend  cold  through  180  deg.  flat  on  itself  without  cracking  on  the  out- 
side of  the  bent  portion. 

b  Hot-bend  Tests — The  test  specimen,  when  heated  to  a  bright 
cherry  red,  shall  bend  through  180  deg.  flat  on  itself,  without  fracture 
on  the  outside  of  the  bent  portion. 

c  Nick-bend  Tests — The  test  specimen,  when  nicked  25  per  cent 
around  with  a  tool  having  a  60-deg.  cutting  edge,  to  a  depth  of  not 
less  than  8  nor  more  than  1.6  per  cent  of  the  diameter  of  the  specimen, 
and  broken,  shall  show  a  wholly  fibrous  fracture. 

d     Bend  tests  may  be  made  by  pressure  or  by  blows. 


32  REPORT  OF  BOILER  CODE  COMMITTEE,  AM.ROC.M.E 

125  Etch  T>es1s.1     The  cross-section  of  the  test  specimen  shall  be 
ground  or  polished,  and  etched  for  a  sufficient  period  to  develop  the 
structure.    This  test  shall  show  the  material  to  he  free  from  steel. 

126  Test  Specimens.     All  test  specimens  shall  he  of  the  full  sec- 
tion of  material  as  rolled. 

1.27  Number  of  Tests,  a  Bars  of  one  size  shall  be  sorted  into 
lots  of  100  each.  Two  bars  shall  be  selected  at  random  from  each  Jot 
or  fraction  thereof,  and  tested  as  specified  in  Pars.  123  and  124;  but 
only  one  of  these  bars  shall  be  tested  as  specified  in  Par.  125. 

b  If  any  test  specimen  from  either  of  the  bars  originally  selected 
to  represent  a  lot  of  material,  contains  surface  defects  not  visible  before 
testing  but  visible  after  testing,  or  if  a  tension  test  specimen  breaks 
outside  the  middle  third  of  the  gage  length,  one  retest  from  a  different 
bar  will  be  allowed. 

ITT     PERMISSIBLE  VARIATIONS  IN  GAGE 

128  Permissible  Variations.     The  gage  of  each  bar  shall  not  vary 
more  than  0.01  in.  from  that  specified. 

IV  FINISH 

129  Finish.     The  bars  shall  be  smoothly  rolled  and  free  from 
slivers,  depressions,  seams,  crop  ends  and  evidences  of  being  burnt. 

V  MARKING 

130  Marking.     The  bars  shall  be  stamped  or  marked  as  desig- 
nated by  the  purchaser. 

VI     INSPECTION"  AND  REJECTION 

131  Inspection,     a     The   inspector   representing  the   purchaser 
shall  have  free  entry  at  all  times,  while  work  on  the  contract  of  the 
purchaser  is  being  performed,  to  all  parts  of  the  manufacturer's  works 
which  concern  the  manufacture  of  the  material  ordered.     The  manu- 
facturer shall  afford  the  inspector,  free  of  cost,  all  reasonable  facilities 
to  satisfy  him  that  the  material  is  being  furnished  in  accordance  with 


1A  solution  of  two  parts  water,  one  part  concentrated  hydrochloric  acid,  and  one  part  concen- 
trated sulphuric  acid  is  recommended  for  the  etch  test. 


NEW  INSTALLATIONS,  PART  I,  SECTION  I.  POWER  BOILERS  33 

these  specifications.    Tests  and  inspection  at  the  place  of  manufacture 
shall  he  made  prior  to  shipment. 

b  The  purchaser  may  make  the  tests  to  govern  the  acceptance  or 
rejection  of  material  in  his  own  laboratory  or  elsewhere.  iSuch  tests, 
however,  shall  be  made  at  the  expense  of  the  purchaser. 

132  Rejection.     If  either  of  the  test  bars  selected  to  represent  a 
lot  does  not  conform  to  the  requirements  specified  in  Pars.  123,  124 
and  125,  the  lot  will  be  rejected. 

B    REQUIREMENTS  FOR  RIVETS 
I     PHYSICAL  PROPERTIES  AND  TESTS 

133  Number  of  'Tests.     When  specified,  three  rivets  of  each  di- 
ameter shall  be  taken  at  random  from  each  lot  offered  for  inspection, 
and  if  they  fail  to  stand  the  following  tests  the  lot  will  be  rejected. 

134  Bend  -Tests,     a     The  rivet  shank  shall  bend  cold  through 
180  deg.  flat  on  itself,  as  shown  in  Fig.  2,  without  cracking  on  the  out- 
side of  the  bent  portion. 

b  The  heads  must  stand  bending  back,  showing  that  they  are 
firmly  joined. 

c  When  nicked  and  broken  gradually  the  fracture  must  show  a 
clean,  long  and  fibrous  iron. 

II     WORKMANSHIP  AND  FINISH 

135  Workmanship.     The  rivets  shall  be  true  to  form,  concentric, 
and  shall  be  made  in  a  workmanlike  manner. 

13$    Finish.     The  finished  rivets  shall  be  free  from  injurious  de- 


fects. 

, 

III     INSPECTION  AND  REJECTION 

137  Inspection.  The  inspector  representing  the  purchaser  shall 
have  free  entry  at  all  times,  while  work  on  the  contract  of  the  pur- 
chaser is  being  performed,  to  all  parts  of  the  manufacturer's  works 
which  concern  the  manufacture  of  the  rivets  ordered.  The  manu- 
facturer shall  afford  the  inspector,  free  of  cost,  all  reasonable  facilities 
to  satisfy  him  that  the  rivets  are  being  furnished  in  accordance  with 
these  specifications.  All  tests  and  inspection  shall  be  made  at  the 


34  REPORT  OF  BOILER  CODE  COMMITTEE,  AM.SOC.M.E. 

place  of  manufacture  prior  to  shipment,  unless  otherwise  specified,  and 
shall  be  so  conducted  as  not  to  interfere  unnecessarily  with  the  opera- 
tion of  the  works. 

13$  Rejection.  Rivets  which  show  injurious  defects  subsequent 
to  their  acceptance  at  the  manufacturer's  works  will  be  rejected,  and 
the  manufacturer  shall  be  notified. 


SPECIFICATIONS  FOR  STAYBOLT  IRON 

THESE  SPECIFICATIONS  ARE  IDENTICAL  WITH  THOSE  OF  THE 
AMERICAN  SOCIETY  FOR  TESTING  MATERIALS,  SERIAL  DESIGNATION 
A  39-14. 

I    MANUFACTURE 

139  Process.     The  iron  shall  be  rolled  from  a  bloom  or  boxpile, 
made  wholly  from  puddled   iron   or  knobbled   charcoal   iron.     The 
puddle  mixture  and  the  component  parts  of  the  bloom  or  boxpile  shall 
be  free  from  any  admixture  of  iron  scrap  or  steel. 

140  Definition  of  Terms,     a    Bloom — A  bloom  is  a  solid  mass  of 
iron  that  has  been  hammered  into  a  convenient  size  for  rolling. 

6  Boxpile — A  boxpile  is  a  pile,  the  sides,  top  and  bottom  of  which 
are  formed  by  four  flat  bars  and  the  interior  of  which  consists  of  a 
number  of  small  bars  the  full  length  of  the  pile. 

c  Iron  Scrap — This  term  applies  only  to  foreign  or  purchased 
scrap  and  does  not  include  local  mill  products  free  from  foreign  or 
purchased  scrap. 

II     PHYSCIAL  PROPERTIES  AND  TESTS 

141  Tension  Tests,     a     The  iron  shall  conform  to  the  following 
requirements  as  to  tensile  properties: 

Tensile  strength,  Ib.  per  sq.  in 49,000-53,000 

Yield  point,  min.,  Ib.  per  sq.  in O.C  tens.  str. 

Elongation  in  8  in.,  min.,  per  cent 30 

Reduction  of  area,  min.,  per  cent 48 

&  The  yield  point  shall  be  determined  by  the  drop  of  the  beam 
of  the  testing  machine.  The  speed  of  the  cross-head  of  the  machine 
shall  not  exceed  1%  in.  per  minute. 


NEW  INSTALLATIONS,  PART  I,  SECTION  I,  POWER  BOILERS  35 

142  Bend  Tests,     a     Cold-lend  Tests — The  test  specimen  shall 
bend  cold  through  180  deg.  flat  on  itself  in  both  directions  withoul 
fracture  on  the  outside  of  the  bent  portion. 

b  Quench-bend  Tests — The  test  specimen,  when  heated  to  a  yel- 
low heat  and  quenched  at  once  in  water  the  temperature  of  which  is 
between  80  deg.  and  90  deg.  fahr.,  shall  bend  through  180  deg.  flat  on 
itself  without  fracture  on  the  outside  of  the  bent  portion. 

c  Nick-lend  Tests — The  test  specimen,  when  nicked  25  per  cent 
around  with  a  tool  having  a  60-deg.  cutting  edge,  to  a  depth  of  not 
less  than  8  nor  more  than  16  per  cent  of  the  diameter  of  the  specimen, 
and  broken,  shall  show  a  clean  fiber  entirely  free  from  crystallization. 

d     Bend  tests  may  be  made  by  pressure  or  by  blows. 

143  Etch  Tests*     The  cross-section  of  the  test  specimen  shall  be 
ground  or  polished,  and  etched  for  a  sufficient  period  to  develop  the 
structure.    This  test  shall  show  the  material  to  have  been  rolled  from 
a  bloom  or  a  boxpile,  and  to  be  free  from  steel. 

144  Test  Specimens.     All  test  specimens  shall  be  of  the  full  sec- 
tion of  material  as  rolled. 

145  Number  of  Tests,     a     Bars  of  one  size  shall  be  sorted  into 
lots  of  100  each.    Two  bars  shall  be  selected  at  random  from  each  lot 
or  fraction  thereof,  and  tested  as  specified  in  Pars.  141  and  142<;  but 
only  one  of  these  bars  shall  be  tested  as  specified  in  Par.  143. 

1)  If  any  test  specimen  from  either  of  the  bars  originally  selected 
to  represent  a  lot  of  material,  contains  surface  defects  not  visible  be- 
fore testing  but  visible  after  testing,  or  if  a  tension  test  specimen 
breaks  outside  the  middle  third  of  the  gage  length,  one  retest  from  a 
different  bar  will  be  allowed. 

c  When  retests  as  specified  in  b  are  not  permitted,  a  reduction 
of  2  per  cent  in  elongation  and  3  per  cent  in  reduction  of  area  from 
that  specified  in  Par.  141,  shall  be  allowed. 


Ill     PERMISSIBLE  VARIATIONS  IN  GAGE 

146.  Permissible  Variations.  The  bars  shall  be  truly  round 
within  0.01  in.,  and  shall  not  vary  more  than  0.005  in.  above  or  more 
than  0.01  in.  below  the  specified  size. 


*A  solution  of  two  parts  water,  one  part  concentrated  hydrochloric  acid,  and  one  part  concen- 
«r«ted  sulphuric  acid  is  recommended  for  the  etch  test. 


36  REPORT  OF  BOILER  CODE  COMMITTEE,   AM.SOC.M.E. 

IV  FINISH 

147  Finish.     The  bars  shall  be  smoothly  rolled  and  free  from 
slivers,  depressions,  seams,  crop  ends  and  evidences  of  being  burnt. 

V  MARKING 

148  Marking.     The  bars  shall  be  stamped  or  marked  as  desig- 
nated by  the  purchaser. 

VI    INSPECTION  AND  REJECTION 

149  Inspection,     a     The   inspector   representing   the   purchaser 
shall  have  free  entry,  at  all  times  while  work  on  the  contract  of  the 
purchaser  is  being  performed,  to  all  parts  of  the  manufacturer's  works 
which  concern  the  manufacture  of  the  material  ordered.     The  manu- 
facturer shall  afford  the  inspector,  free  of  cost,  all  reasonable  facilities 
to  satisfy  him  that  the  material  is  being  furnished  in  accordance  with 
these  specifications.  Tests  and  inspection  at  the  place  of  manufacture 
shall  be  made  prior  to  shipment. 

&  The  purchaser  may  make  the  tests  to  govern  the  acceptance  or 
rejection  of  material  in  his  own  laboratory  or  elsewhere.  Such  tests, 
however,  shall  be  made  at  the  expense  of  the  purchaser. 

150  Rejection,     a     If  either  of  the  test  bars  selected  to  represent 
a  lot  does  not  conform  to  the  requirements  specified  in  Pars.  141,  142 
and  143,  the  lot  will  be  rejected. 

b  Bars  which  will  not  take  a  clean,  sharp  thread  with  dies  in  fair 
condition,  or  which  develop  defects  in  forging  or  machining,  will  be 
rejected,  and  the  manufacturer  shall  be  notified. 


NEW  INSTALLATIONS,  PART  I,  SECTION  I,  POWER  BOILERS  37 

SPECIFICATIONS  FOR  REFINED  WROUGHT-IRON 

BARS 

THESE  SPECIFICATIONS  ARE  SIMILAR  TO  THOSE  OF  THE  AMERICAN 
SOCIETY  FOR  TESTING  MATERIALS,  SERIAL  DESIGNATION  A  41-13. 

I     MANUFACTURE 

151  Process.     Iiefined  wrought-iron  bars  shall  be  made  wholly 
from  puddled  iron,  and  may  consist  either  of  new  muck-bar  iron  or  a 
mixture  of  muck-bar  iron  and  scrap,  but  shall  be  free  from  any  ad- 
mixture of  steel. 

II     PHYSICAL  PKOPERTIKS  AND  TESTS 

152  Tension  Tests,     a     The  iron  shall  conform  to  the  following 
minimum  requirements  as  to  tensile  properties. 

Tensile  strength,  Ib.  per  sq.  in 48,000 

(See  Pars.  153  and  154.) 

Yield  point,  Ib.  per  sq.  in 25,000 

Elongation  in  8  in.,  per  cent 22 

(See  Par.  155.) 

1)  The  yield  point  shall  be  determined  by  the  drop  of  tlic  beam 
of  the  testing  machine.  The  speed  of  the  cross-head  of  the  machine 
shall  not  exceed  l1/^  in.  per  minute. 

153  Permissible  Variations.     Twenty  per  cent  of  the  test  speci- 
mens representing  one  size  may  show  tensile  strengths  1000  Ib.  per 
sqi'in.  under,,  or  5000  Ib.  per  sq.  in.  over  that  specified  in  Par.  152; 
but  no  specimen  shall  show  a  tensile  strength  under  45,000  Ib.  per 
sq.  in. 

154  Modifications  in  Tensile  Strength.    For  flat  bars  which  have 
to  be  reduced  in  width,  a  deduction  of  1000  Ib.  per  sq.  in.  from  the 
tensile  strength  specified  in  Pars.  152  and  153,  shall  be  made. 

155  Permissible  Variations  in  Elongation.    .Twenty  per  cent  of 
the  test  specimens  representing  one  size  may  show  the  following  per- 
centages of  elongation  in  8  in. : 

BOUND  BAES 

%  in.  or  over,  tested  as  rolled 20  per  cent 

Under  %  in.,  tested  as  rolled 16  per  cent 

Eeduced  by  machining 18  per  cent 


38  REPORT  OF  BOILER  CODE  COMMITTEE,  AM.SOC.M.E. 

FLAT  BARS 

%  in.  or  over,  tested  as  rolled 18  per  cent 

Under  %  in.,  tested  as  rolled 16  per  cent 

Reduced  by  machining 16  per  cent 

15G  Bend  Tests,  a  Cold-bend  Tests — Cold  bend  tests  will  be 
made  only  on  bars  having  a  nominal  area  of  4  sq.  in.  or  under,  in 
which  case  the  test  specimen  shall  bend  cold  through  180  deg.  without 
fracture  on  the  outside  of  the  bent  portion,  around  a  pin  the  diameter 
of  which  is  equal  to  twice  the  diameter  or  thickness  of  the  specimen. 

1)  Hot-bend  Tests — The  test  specimen,  when  heated  to  a  tempera- 
ture between  1700  deg.  and  1800  deg.  fahr.,  shall  bend  through  180 
deg.  without  fracture  on  the  outside  of  the  bent  portion,  as  follows: 
for  round  bars  under  2  sq.  in.  in  section,  flat  on  itself;  for  round  bars 
2  sq.  in.  or  over  in  section  and  for  all  flat  bars,  around  a  pin  the 
diameter  of  which  is  equal  to  the  diameter  or  thickness  of  the  specimen. 

c  Nick-lend  Tests — The  test  specimen,  when  nicked  25  per  cent 
around  for  round  bars,  and  along  one  side  for  flat  bars,  with  a  tool 
having  a  60-deg.  cutting  edge,  to  a  depth  of  not  less  than  8  nor  more 
than  16  per  cent  of  the  diameter  or  thickness  of  the  specimen,  and 
broken,  shall  not  show  more  than  10  per  cent  of  the  fracture  surface 
to  be  crystalline. 

d     Bend  tests  may  be  made  by  pressure  or  by  blows. 

157  Etch  Tests.1     The  cross-section  of  the  test  specimen  shall  be 
ground  or  polished,  and  etched  for  a  sufficient  period  to  develop  the 
structure.    This  test  shall  show  the  material  to  be  free  from  steel. 

158  Test  Specimens,     a     Tension  and  bend  test  specimens  shall 
be  of  the  full  section  of  material  as  rolled,  if  possible;  otherwise  the 
specimens  shall  be  machined  from  the  material  as  rolled.     The  axis 
of  the  specimen  shall  be  located  at  any  point  one-half  the  distance 
from  the  center  to  the  surface  of  round  bars,  or  from  the  center  to 
the  edge  of  flat  bars,  and  shall  be  parallel  to  the  axis  of  the  bar. 

b  Etch  test  specimens  shall  be  of  the  full  section  of  material  as 
rolled. 

159  Number  of  Tests,     a     All  bars  of  one  size  shall  be  piled 
separately.  One  bar  from  each  100  or  fraction  thereof  will  be  selected 
at  random  and  tested  as  specified. 

b  If  any  test  specimen  from  the  bar  originally  selected  to  repre- 
sent a  lot  of  material  contains  surface  defects  not  visible  before  test- 


JA  solution  of  two  parts  water,  one  part  concentrated  hydrochloric  acid,  and  one  part  con- 
centrated sulphuric  acid  is  recommended  for  the  etch  test. 


NEW  INSTALLATIONS,  TART  I,  SECTION  I,  TOWER  BOILERS 


.",0 


ing  but  visible  after  testing,  or  if  a  tension  test  specimen  breaks  outside 
the  middle  third  of  the  gage  length,  one  retest  from  a  different  bar 
will  be  allowed. 

Ill     PERMISSIBLE  VARIATIONS  IN  GAGE 

160  Permissible  Variations,  a  Bound  bars  shall  conform  to  the 
standard  limit  gages  adopted  by  the  Master  Car  Builders'  Association 
given  in  Table  2. 

TABLE  2    PERMISSIBLE  VARIATIONS  IN  GAGE  FOR  ROUND  WROUGHT-IRON  BARS 


Nominal 
Diameter, 
Inches 

Maximum 
Diameter, 
Inches 

Minimum 
Diameter, 
Inches 

Total 
Variation, 
Inches 

y 

0  2550 

0  9450 

0  010 

$ 

0.3180 

0.3070 

0.011 

a/ 

0.3810 

0  3690 

0.012 

JL 

0.4440 

0  4310 

0.013 

j  / 

0  5070 

0  4930 

0.014 

A 

0  5700 

0  5550 

0  015 

%'. 

0  6330 

0.6170 

0.016 

%.  .                         ....... 

0  .  7585 

0.7415 

0.017 

Ys-. 

0.8840 

0.86GO 

0.018 

1 

1   0095 

0  .  9905 

0.019 

1H-  • 

1.1350 

1.1150 

0.020 

1M  

1  .  2605 

1  .  2395 

0.021 

I  The  widths  or  thicknesses  of  flat  bars  shall  not  vary  more  than 
2  per  cent  from  that  specified. 

IV     FINISH 

161  Finish.     The  bars  shall  be  smoothly  rolled  and  free  from 
slivers,  depressions,  seams,  crop  ends  and  evidences  of  being  burnt. 

V    INSPECTION  AND  REJECTION 

162  Inspection,     a     The  inspector  representing  the   purchaser 
shall  have  free  entry,  at  all  times  while  work  on  the  contract  of  the 
purchaser   is  being  performed,   to   all   parts   of  the  manufacturer's 
works  which  concern  the  manufacture  of  the  material  ordered.     The 
manufacturer  shall  afford  the  inspector,  free  of  cost,  all  reasonable 
facilities  to  satisfy  him  that  the  material  is  being  furnished  in  ac- 
cordance with  these  specifications.     Tests  and  inspection  at  the  place 
of  manufacture  shall  be  made  prior  to  shipment. 

I  The  purchaser  may  make  the  tests  to  govern  the  acceptance 
or  rejection  of  material  in  his  own  laboratory  or  elsewhere.  Such 
tests,  however,  shall  be  made  at  the  expense  of  the  purchaser. 


40  REPORT  OF  BOILER  CODE  COMMITTEE,  AM.SOC.M.E. 

163  Rejection.  All  bars  of  one  size  will  be  rejected  if  the  test 
specimens  representing  that  size  do  not  conform  to  the  requirements 
specified. 


SPECIFICATIONS  FOR  LAPWELDED  AND  SEAMLESS 
BOILER  TUBES 

Approved  by  the  Boiler  Tube  Manufacturers  of  America 
September  25,  1914 

I     MANUFACTURE 

164  Process,  a  Lapwelded  tubes  shall  be  made  of  open-hearth 
steel  or  knobbled  hammered  charcoal  iron. 

I)     Seamless  tubes  shall  be  made  of  open-hearth  steel. 

II  €HEMICAL  PROPERTIES  AND  TESTS 

16-5  Chemical  Composition,  a  The  steel  shall  conform  to  the 
following  requirements  as  to  chemical  composition: 

Carbon 0.08-0.18     per  cent 

Manganese     . 0.30-0.50     per  cent 

Phosphorus not  over  0.04     per  cent 

Sulphur    not  over  0.045  per  cent 

1}     Chemical  analyses  will  not  be  required  for  charcoal  iron  tubes. 

166  Clieclc  Analyses,     a     Analyses  of  two  tubes'  in  each  lot  of 
250  (or  on  total  order  if  less  than  260)  may  be  made  by  the  purchaser 
which  shall  conform  to  the  requirements  specified  in  Par.  165.    Drill- 
ings for  analyses  shall  be  taken  from  several  points  around  each  tube. 

1)  If  the  analysis  of  only  one  tube  does  not  conform  to  the  re- 
quirements specified,  analyses  of  two  additional  tubes  from  the  same 
lot  shall  be  made,  each  of  which  shall  conform  to  the  requirements 
specified. 

III  PHYSICAL  PROPERTIES  AND  TESTS 

167  Flange  Test,    a    A  test  specimen  not  less  than  4  in.  in  length 
shall  have  a  flange  turned  over  at  right  angles  toHhe  body  of  the  tube 


NEW  INSTALLATIONS,  PART  I,  SECTION  I,  POWER  BOILERS 


41 


without  showing  cracks  or  flaws.  This  flange  as  measured  from  the 
outside  of  the  tube  shall  be  %  in.  wide. 

I  In  making  the  flange  test,  the  flaring  tool  and  die  block  as 
shown  in  Fig.  7,  may  be  used. 

168  Flattening  Tests.  A  test  specimen  3  in.  in  length  shall 
stand  hammering  flat  until  the  inside  walls  are  brought  parallel  and 
separated  by  a  distance  equal  to  three  (3)  times  the  wall  thickness, 
without  showing  cracks  or  flaws.  In  the  case  lapwelded  tubes,  the. 
test  shall  be  made  with  the  weld  at  the  point  of  maximum  bend. 


-FT 


<    CO 


FLARING  TOOL 
A  =  O.S.  Diam.  of  Tube,  less 

C  =   "         "       »•      "  plus 


Position  after  using  riarinq  Tool 
V     Position  after  using 

-'         Flatter 


A  - 

DIE  BLOCK 
A  =  O.S.  Diam.  of  Tube  #  ^ 


FIG.  7    DETAILS  OF  FLARING  TOOL  AND  DIE  BLOCK  EEQUIRED  FOR  MAKING 
FLANGE  TESTS  OF  BOILER  TUBES 


169  Hydrostatic  Tests.  Tubes  under  5  in.  in  diameter  shall  stand 
an  internal  hydrostatic  pressure  of  'lOOO  Ib.  per  sq.  in.  and  tubes  5  in. 
in  diameter  or  over,  an  internal  hydrostatic  pressure  of  800  Ib.  per  sq. 
in.    Lapwelded  tubes  shall  be  struck  near  both  ends,  while  under  pres- 
sure, with  a  two-pound  hand  hammer  or  the  equivalent. 

170  Test  Specimens,     a     All  test  specimens  shall  be  taken  from 
tubes  before  being  cut  to  finished  lengths  and  shall  be  smooth  on  the 
ends  and  .free  from  burrs,    b    All  tests  shall  be  made  cold. 

171  Number  of  Tests.     One  flange  and  one  flattening  test  shall 
be  made  from  each  of  two  tubes  in  each  lot  of  250  or  less.    Each  tube 
shall  be  subjected  to  the  hydrostatic  test. 

172  Retests.     If  the  result  of  the  physical  tests  of  only  one  tube 
from  any  lot  do  not  conform  to  the  requirements  specified  in  Pars.  167 
and  168,  retests  of  two  additional  tubes  from  the  same  lot  shall  be 
made,  each  of  which  shall  conform  to  the  requirements  specified, 


42  REPORT  OF  BOILER  CODE  COMMITTEE,  AM.SOC.M.E. 

ETCH    TESTS    FOR    CHARCOAL    IRON 

1,73  Etch  Tests*  A  cross  section  of  tube  may  be  turned  or 
ground  to  a  perfectly  true  surface  polished  free  from  dirt  or  cracks, 
and  etched  until  the  soft  parts  are  sufficiently  dissolved  for  the  iron 
tube  to  show  a  decided  ridged  surface  with  the  weld  very  distinct, 
while  a  steel  tube  would  show  a  homogeneous  surface. 

IV    WORKMANSHIP  AND  FINISH 

174  Workmanship.     The  finished  tubes  shall  be  circular  within 
0.02  in.  and  the  mean  outside  diameter  shall  not  vary  more  than  0.015 
in.  from  the  size  ordered.     All  tubes  shall  be  carefully  gaged  with  a 
B.W.G.  gage  and  shall  not  be  less  than  the  gage  specified,  except 
the   tubes   on  which  the  standard   slot  gage,   specified,   will   go   on 
tightly  at  the  thinnest  point,  will  be  accepted.     The  length  shall  not 
be  less,  but  may  be  0.125  in.  more  than  that  ordered. 

175  Finish.     The  finished  tubes  shall  be  free  from  injurious  de- 
fects and  shall  have  a  workmanlike  finish  and  shall  be  practically  free 
from  kinks,  bends  and  buckles. 

V    MARKING 

176  Marking.     The  name  or  brand  of  the  manufacturer,  the  ma- 
terial from  which  it  is  made,  whether  steel  or  charcoal  iron,  and 
"Tested  at  1000  Ib."  for  tubes  under  5  in.  in  diameter,  or  "Tested  at 
800  Ib."  for  tubes  5  in.  in  diameter  or  over,  shall  be  legibly  stenciled 
on  each  tube. 

VI     INSPECTION  AND  REJECTION 

1-77  Inspection.  All  tests  and  inspection  shall  be  made  at  the 
place  of  manufacture.  The  manufacturer  of  boiler  tubes  shall  furnish 
the  purchaser  of  each  lot  of  tubes  a  statement  of  the  kind  of  material 
of  which  the  tubes  are  made,  and  that  the  tubes  have  been  tested  and 
have  met  all  the  requirements  of  these  rules.  This  statement  shall  be 
furnished  to  the  manufacturer  using  the  tubes. 

178  Rejection.  Tubes  when  inserted  in  the  boiler  shall  stand 
expanding  and  beading  without  showing  cracks  or  flaws,  or  opening 
at  the  weld.  Tubes  which  fail  in  this  manner  will  be  rejected  and  the 
manufacturer  shall  be  notified. 


1A  solution  of  two  parts  of  water,  one  part  concentrated  hydrochloric  acid,  and  one  part 
concentrated  sulphuric  acid  is  recommended  for  the  etch  test. 


NEW  INSTALLATIONS,  TART  I,  SECTION  I,  PG  .VEll  BOILERS  43 


CONSTRUCTION  AND  MAXIMUM  ALLOWABLE  WORKING  PRESSURES 
POR  POWER  BOILERS 

179  Maximum  Allowable  Working  Pressure.  The  maximum  al- 
lowable working  pressure  is  that  at  which  a  boiler  may  be  operated  as 
determined  by  employing  the  factors  of  safety,  stresses,  and  dimensions 
designated  in  these  Rules. 

No  boiler  shall  be  operated  at  a  higher  pressure  than  the  maxi- 
mum allowable  working  pressure  except  when  the  safety  valve  or 
valves  are  blowing,  at  which  time  the  maximum  allowable  working 
pressure  shall  not  be  exceeded  by  more  than  six  per  cent. 

Wherever  the  term  maximum  allowable  working  pressure  is  used 
herein,  it  refers  to  gage  pressure,  or  the  pressure  above  the  atmosphere, 
in  pounds  per  square  inch. 

18>0  The  maximum  allowable  working  pressure  on  the  shell  of  a 
boiler  or  drum  shall  be  determined  by  the  strength  of  the  weakest 
course,  computed  from  the  thickness  of  the  plate,  the  tensile  strength 
stamped  thereon,  as  provided  for  in  Par.  36,  the  efficiency  of  the 
longitudinal  joint,  or  of  the  ligament  between  the  tube  holes  in  shell 
or  drum,  (whichever  is  the  least),  the  inside  diameter  of  the  course, 
and  the  factor  of  the  safety. 

•=  maximum  allowable  working  pressure,  Ib.  per  sq.  in. 
» 

where 

TS  =  ultimate  tensile  strength  stamped  on  shell  plates,  as 
provided  for  in  Par.  36,  Ib.  per  sq.  in. 

t  =  minimum  thickness  of  shell  plates  in  weakest  course,  in. 

E  —  efficiency  of  longitudinal  joint  or  of  ligaments  between 
tube  holes  (whichever  is  the  least) 

E  =  inside  radius  of  the  weakest  course  of  the   shell   or 
drum,  in. 

F8  =  factor  of  safety,  or  the  ratio  of  the  ultimate  strength  of 
the  material  to  the  allowable  stress.  For  new  con- 
structions covered  in  Part  I,  FS  in  the  above  for- 
mula =  5. 


44  REPORT  OF  BOILER  CODE  COMMTTTEE,  AM.SOC.M.E. 

BOILER  JOINTS 

181  Efficiency  of  a  Joint.     The  efficiency  of  a  joint  is  the  ratio 
which  the  strength  of  the  joint  bears  to  the  strength  of  the  solid 
plate.    In  the  case  of  a  riveted  joint  this  is  determined  by  calculating 
the  breaking  strength  of  a  unit  section  of  the  joint,  considering  each 
possible  mode  of  failure  separately,  and  dividing  the  lowest  result  by 
the  breaking  strength  of  the  solid  plate  of  a  length  equal  to  that  of  the 
section  considered.      ('See  Appendix,  Par.  410  to  416,  for  detailed 
methods  and  examples.) 

182  The  distance  between  the  center  lines  of  any  two  adjacent 
rows  of  rivets,  or  the  "back  pitch"  measured  at  right  angles  to  the 
direction  of  the  joint,  shall  be  at  least  twice  the  diameter  of  the  rivets 
and  shall  also  meet  the  following  requirements : 

d  Where  each  rivet  in  the  inner  row  comes  midway  between 
two  rivets  in  the  outer  row,  the  sum  of  the  two  diagonal 
sections  of  the  plate  between  the  inner  rivet  and  the  two 
outer  rivets  shall  be  at  least  20  per  cent  greater  than  the 
section  of  the  plate  between  the  two  rivets  in  the  outer 
row. 

&  Where  two  rivets  in  the  inner  row  come  between  two  rivets 
in  the  outer  row,  the  sum  of  the  two  diagonal  sections  of 
the  plate  between  the  two  inner  rivets  and  the  two  rivets 
in  the  outer  row  shall  be  at  least  20  per  cent  greater  than 
the  difference  in  the  section  of  the  plate  between  the  two 
rivets  in  the  outer  row  and  the  two  rivets  in  the  inner  row. 

183  On  longitudinal  joints,   the  distance  from  the  centers   of 
rivet  holes  to  the  edges  of  the  plates,  except  rivet  holes  in  the  ends  of 
butt  straps,  shall  be  not  less  than  one  and  one-half  times  the  diameter 
of  the  rivet  holes. 

184  a     Circumferential  Joints.    The  strength  of  circumferential 
joints  of  boilers,  the  heads  of  which  are  not  stayed  by  tubes  or  through 
braces  shall  be  at  least  50  per  cent  that  of  the  longitudinal  joints  of  the 
same  structure. 

1}  When  50  per  cent  or  more  of  the  load  which  would  act  on  an 
r.nstayed  solid  head  of  the  same  diameter  as  the  shell,  is  relieved  by  the 
effect  of  tubes  or  through  stays,  in  consequence  of  the  reduction  of  the 
area  acted  on  by  the  pressure  and  the  holding  power  of  the  tubes  and 
stays,  the  strength  of  the  circumferential  joints  in  the  shell  shall  be 
at  least  35  per  cent  that  of  the  longitudinal  joints. 

185  When  she'll  plates  exceed  9/16  in.  in  thickness  in  horizontal 


NEW  INSTALLATIONS,   PART   I,   SECTION  I,  POWER  BOILERS 


4T, 


return  tubular  boilers,  the  portion  of  the  plates  forming  the  laps  of  the 
circumferential  joints,  where  exposed  to  the  fire  or  products  of  com- 
bustion, shall  be  planed  or  milled  down  as  shown  in  Fig.  8,  to  !/2  in- 
in  thickness,  provided  the  requirement  in  Par.  184  is  complied  with. 

18.6  Welded  Joints.  Tho  ultimate  tensile  strength  of  a  longi- 
tudinal joint  which  has  been  properly  welded  by  the  forging  process, 
shall  be  taken  as  28,500  Ib.  per  sq.  in.,  with  steel  plates  having  a  range 
in  tensile  strength  of  47,000  to  55,000  Ib.  per  sq.  in. 

187  Longitudinal  Joints.     The  longitudinal  joints  of  a  shell  or 
drum  which  exceeds  36  in.  in  diameter,  shall  be  of  butt  and  double- 
strap  construction. 

188  The  longitudinal  joints  of  a  shell  or  drum  which  does  not 


FIG.  8 


CIRCUMFERENTIAL  JOINT  FOR  THICK  PLATES  OF  HORIZONTAL  KETURN 
TUBULAR  BOILERS 


exceed  36  in.  in  diameter,  may  be  of  lap-riveted  construction ;  but  the 
maximum  allowable  working  pressure  shall  not  exceed  100  Ib.  per 
sq.  in. 

189  The  longitudinal  joints  of  horizontal  return  tubular  boilers 
shall  be  located  above  the  fire-line  of  the  setting, 

190  A  horizontal  return  tubular  boiler  on  which  a  longitudinal 
lap  joint  is  permitted  shall  not  have  a  course  over  12  ft.  in  length. 
With  butt  and  double-strap  construction,  longitudinal  joints  of  any 
length  may  be  used  provided  the  plates  are  tested  transversely  to 
the  direction  of  rolling,  which  tests  shall  show  the  standards  pre- 
scribed under  the  Specifications  of  Boiler  Plate  Steel. 

191  Butt  straps  and  the  ends  of  shell  plates  forming  the  longi- 
tudinal joints  shall  be  rolled  or  formed  by  pressure,  not  blows,  to  the 
proper  curvature. 


46  HEl'ORT  OF  BOILER  CODE  COMMITTEE,  AM.SOC.M.E. 

LIGAMENTS 

192    Efficiency  of  Ligament.     "When  a  shell  or  drum  is  drilled  for 

tubes  in  a  line  parallel  to  the  axis  of  the  shell  or  drum,  the  efficiency 

of  the  ligament  between  the  tube  holes  shall  be  determined  as  follows : 

a  When  the  pitch  of  the  tube  holes  on  every  row  is  equal  (Fig. 

9 ) ,  the  formula  is : 


where 


.1. =  efficiency  of  ligament 

P 

p  =  pitch  of  tube  holes,  in. 
d  =  diameter  of  tube  holes,  in. 


Longitudinal   Line  — - 


FIG.  9    EXAMPLE  OF  TUBE  SPACING  WITH  PITCH  OF 
HOLES  EQUAL  IN  EVERY  Row 

Example:  Pitch  of  tube  holes  in  the  drum  as  shown  in  Fig.  9 
=  5!/4  in.  Diameter  of  tubes  =  3^  in.  Diameter  of  tube  holes  = 
3  9/32  in. 

p—d       5.25—3.281 

= — ^ =  0.375,  efficiency  of  ligament 


* 


-e-e-^ 


.Longitudinal  Line 

FIG.  10    EXAMPLE  OF  TUBE  SPACING  WITH  PITCH 
OF  HOLES  UNEQUAL  IN  EVERY  SECOND  Eow 

When  the  pitch  of  tube  holes  on  any  one  row  is  unequal  (as 
in  Figs.  10  or  11),  the  formula  is: 

L-      -  =  efficiency  of  ligament 


where 


NEW  INSTALLATIONS,  FART  I,  SECTION  I,  POWER  BOILERS  47 

p  =  unit  length  of  ligament,  in. 

n  =  number  of  tube  holes  in  length,  p. 

d  =  diameter  of  tube  holes,  in. 

Example:     Spacing  shown  in  Fig.  10.    Diameter  of  tube  holes  = 
3  9/3-2  in. 

p—nd        12—2X3.281 

—  -  = --3— =  0.453,  efficiency  of  ligament 

p  L/u 

Example:     Spacing  shown  in  Fig.  11.     Diameter  of  tube  holes 
=  3  9/32  in. 

p—nd        29.2.5—5X3.281 

—  -  ==* ^TTT —  0.439,  efficiency  of  ligament 


Longitudinal   Line 


FIG.  11     EXAMPLE  OF  TUBE  SPACING  WITH  PITCH  OF  HOLES 
VARYING  IN  EVERY  SECOND  AND  THIRD  Eow 

193  When  a  shell  or  drum  is  drilled  for  tube  holes  in  a  line 
diagonal  with  the  axis  of  the  shell  or  drum  as  shown  in  Fig.  1>2,  the 
efficiency  of  the  ligament  between  the  tube  holes  shall  be  determined 
by  the  following  methods  and  the  lowest  value  used. 


0.95  (pl—d) 


b 

where 

Pi 
p-d 

P 

=  efficiency  of  ligament 
=  efficiency  of  ligament 


p^  =  diagonal  pitch  of  tube  holes,  in. 
d  =  diameter  of  tube  holes,  in. 

p  =  longitudinal  pitch  of  tube  holes  or  distance  between 
centers  of  tubes  in  a  longitudinal  row,  in. 

The  constant  0.9*5  in  formula  a  applies  provided  ^~  is  1.5  or  over. 


48  REPORT  OF  BOILER  CODE  COMMITTEE,  AM.SOC.M.E. 

Example :     Diagonal  pitch  of  tube  holes  in  drum  as  shown  in  Fig. 
12  =  6.42  in. 

Diameter  of  tube  holes  =  4  1/32  in. 
Longitudinal  pitch  of  tube  holes  =11%  in. 


a 


0.95(6.42—4.03])  ffi. 

i — — — - —  U.d5o,  .efficiency  ol  ligament 


11.5—4.031 
11.5 


=  0.649,  efficiency  of  ligament 


The  value  determined  by  formula  a  is  the  least  and  is  the  one  that 
shall  be  used  in  this  case. 


Longitudinal    Line >• 

FIG.  12     EXAMPLE  OF  TUBE  SPACING  WITH  TUBE  HOLES  ON  DIAGONAL  LINES 


194  Domes.  The  longitudinal  joint  of  a  dome  24  in.  or  over  in 
diameter  shall  be  of  butt  and  double-strap  construction,  and  its  flange 
shall  be  double  riveted  to  the  boiler  shell  when  the  maximum  allowable 
working  pressure  exceeds  100  Ib.  per  sq.  in. 

The  longitudinal  joint  of  a  dome  less  than  24  in.  in  diameter  may 
be  of  the  lap  type,  and  its  flange  may  be  single  riveted  to  the  boiler 
shell  provided  the  maximum  allowable  working  pressure  on  such  a 
dome  is  computed  with  a  factor  of  safety  of  not  less  than  8. 

The  dome  may  be  located  on  the  barrel  or  over  the  fire-box  on 
traction,  portable  or  stationary  boilers  of  the  locomotive  type  up  to 
and  including  48  in.  barrel  diameter.  For  larger  barrel  diameters,  the 
dome  shall  be  placed  on  the  barrel. 


NEW  INSTALLATIONS,  TART  I,  SECTION  I,  POWER  BOILERS        49 
DISHED  HEADS 

195  Convex  Heads.  The  thickness  required  in  an  imstayed 
dished  head  with  the  pressure  on  the  concave  side,  when  it  is  a  seg- 
ment of  a  sphere,  shall  he  calculated  hy  the  following  formula  : 


2XTS 

where 

t  =  thickness  of  plate,  in. 

P  =  maximum  allowable  working  pressure,  Ib.  per  sq.  in. 
TS  =  tensile  strength,  11).  per  sq.  in. 

L  =  radius  to  which  the  head  is  dished,  in. 

Where  the  radius  is  less  than  80  per  cent  of  the  diameter  of  the 
shell  or  drum  to  which  the  head  is  attached  the  thickness  shall  be  at 
least  that  found  by  the  formula  by  making  L  equal  to  80  per  cent  of 
the  diameter  of  the  shell  or  drum. 

Concave  Heads.  Dished  heads  with  the  pressure  on  the  convex 
side  shall  have  a  maximum  allowable  working  pressure  equal  to  60 
per  cent  of  that  for  heads  of  the  same  dimensions  with  the  pressure 
on  the  concave  side. 

When  a  dished  head  has  a  manhole  opening,  the  thickness  as 
found  by  these  Rules  shall  be  increased  by  not  less  than  14  in. 

196  When  dished  heads  are  of  a  less  thickness  than  called  for 
by  Par.  195,  they  shall  be  stayed  as  flat  surfaces,  no  allowance  being 
made  in  such  staying  for  the  holding  power  due  to  the  spherical  form. 

197  The  corner  radius  of  an  unstayed  dished  head  measured  on 
the  concave  side  of  the  head  shall  not  be  less  than  l1/^  in.  or  more 
than  4  in.  and  within  these  limits  shall  be  not  less  than  3  per  cent  of 
L  in  Par.  195. 

198  A  manhole  opening  in  a  dished  head  shall  be  flanged  to  a 
depth  of  not  less  than  three  times  the  thickness  of  the  head  measured 
from  the  outside. 

BRACED  AND  STAYED  SURFACES 

199  The    maximum    allowable    working    pressure    for    various 
thicknesses  of  braced  and  stayed  flat  plates  and  those  which  by  these 
Rules  require   staying  as  flat  surfaces  with  braces  or  staybolts  of  uni- 


50  REPORT  OF  BOILER  CODE  COMMITTEE,  AM.SOC.M.E. 

form    diameter    symmetrically    spaced,    shall    be    calculated    by    the 
formula  : 


p2 
where 

P  =  maximum  allowable  working  pressure,  Ib.  per  sq.  in. 
t  =  thickness  of  plate  in  sixteenths  of  an  inch 

P  =  maximum  pitch  measured  between  straight  lines  passing 
through  the  centers  of  the  staybolts  in  the  different 
rows,  which  lines  may  be  horizontal,  vertical  or  in- 
clined, in. 

C  =  11,2  for  stays  screwed  through  plates  not  over  7/16  in. 
thick  with  ends  riveted  over 

C  —  120  for  stays  screwed  through  plates  over  7/16  in.  thick 
with  ends  riveted  over 

C  =  135  for  stays  screwed  through  plates  and  fitted  with 
single  nuts  outside  of  plate 

C  =  175  for  stays  fitted  with  inside  and  outside  nuts  and 
outside  washers  where  the  diameter  of  washers  is  not 
less  than  QAp  and  thickness  not  less  than  t. 

If  flat  plates  not  less  than  %  in.  thick  are  strengthened  with  doubling 
plates  securely  riveted  thereto  and  having  a  thickness  of  not  less 
than  2/3  t,  nor  more  than  t,  then  the  value  of  t  in  the  formula  shall 
be  %  of  the  combined  thickness  of  the  plates  and  the  values  of  C 
given  above  may  also  be  increased  15  per  cent. 

200  Staybolts.     The  ends  of  screwed  staybolts  shall  be  riveted 
over  or  upset  by  equivalent  process.    The  outside  ends  of  such  staybolts 
shall  be  drilled  with  a  hole  at  least  3/16  in.  diameter  to  a  depth  ex- 
tending y2  in.  beyond  the  inside  of  the  plates,  except  on  boilers  having 
a  grate  area  not  exceeding  15  sq.  ft.,  where  the  drilling  of  the  staybolts 
is  optional. 

201  When  channel  irons  or  other  members  are  securely  riveted 
to  the  boiler  heads  for  attaching  through  stays  the  transverse  stress 
on  such  members  shall  not  exceed  12,500  Ib.  per  sq.  in.    In  computing 
the  stress,  the  section  modulus  of  the  member  shall  be  used  without 
addition  for  the  strength  of  the  plate.    The  spacing  of  the  rivets  over 
the  supported  surface  shall  be  in  conformity  with  that  specified  for 
staybolts. 


NEW  INSTALLATIONS,  PART  I,  SECTION  I,  POWER  BOILERS  51 

203  The  ends  of  stays  fitted  with  nuts  shall  not  be  exposed  to 
the  direct  radiant  heat  of  the  fire. 

203  The  maximum  spacing  between  centers  of  rivets  attaching 
the  crowfeet  of  braces  to  the  braced  surface,  shall  be  determined  by 
the  formula  in  Par.  199,  using  135  for  value  of  C. 

The  maximum  spacing  between  the  inner  surface  of  the  shell  and 
lines  parallel  to  the  surface  of  the  shell  passing  through  the  centers 
of  the  rivets  attaching  the  crowfeet  of  braces  to  the  head,  shall  be 
determined  by  the  formula  in  Par.  199,  using  160  for  the  value  of  C. 


TABLE  3     MAXIMUM  ALLOWABLE  PITCH,  IN  INCHES,  OF  SCREWED  STAYBOLTS, 
ENDS  RIVETED  OVER 


Pressure, 
Lb.  per  Sq.  In. 

Thickness  of  Plate,  la. 

& 

H 

•  A 

X 

A 

5A 

tt 

Maximum  Pitch  of  Staybolts,  In. 

100 
110 
120 
125 
130 
140 
150 
160 
170 
180 
190 
200 
225 
250 
300 

5M 
5 
4M 
4M 

±y* 
±y* 

4M 
±Ys 
4 

\oo  \-)i  \w  \«  \oo  \oo  \a>  \»)i  \ao  \«  \-ji 
wS  «Ss,  >ri\  .-K  c<K  T-\  K\  «i\  iri\  --K  .-K 

7% 

7 

6M 

6^i 
6^ 
6M 
6 

57A 
&A 

sy2 

5*A 

5M 
4^i 
4^ 
4M 

8^ 
8 
7M 
7% 
7H 

7ys 

VA 

&H 
61A 
Q% 

sy* 

VA 
514 
5 

m 

8 
7M 

^l^ 

7Ys 

iy* 

7 
6^ 
6M 
5^ 

8^ 
8H 
77A 
7H 
7M 
6^ 
6M 

"V8Mi" 
8 

7% 
7 

204  The  formula  in  Par.  199  was  used  in  computing  Table  3. 
Where  values  for  screwed  stays  with  ends  riveted  over  are  required  for 
conditions  not  given  in  Table  3,  they  may  be  computed  from  the 
formula  and  used,  provided  the  pitch  does  not  exceed  8l/2  m- 

205  The  distance  from  the  edge  of  a  staybolt  hole  to  a  straight 
line  tangent  to  the  edges  of  the  rivet  holes  may  be  substituted  for  p 
for  staybolts  adjacent  to  the  riveted  edges  bounding  a  stayed  surface. 
When  the  edge  of  a  stayed  plate  is  flanged,  p  shall  be  measured  from 
the  inner  surface  of  the  flange,  at  about  the  line  of  rivets  to  the  edge 
of  the  staybolts  or  to  the  projected  edge  of  the  staybolts. 


52  REPORT  OF  BOILER  CODE  COMMITTEE.  AM.SOC.M.E. 

206  The  distance  between  the  edges  of  the  staybolt  holes  may  be 
substituted  for  p  for  staybolts  adjacent  to  a  furnace  door  or  other 
boiler  fitting,  tube  hole,  hand  hole  or  other  opening. 

207  In  water  leg  boilers,  the  staybolts  may  be  spaced  at  greater 
distances  between  the  rows  than  indicated  in  Table  3,  provided  the 
portions  of  the  sheet  which  come  between  the  rows  of  staybolts  have 
the  proper  transverse  strength  to  give  a  factor  of  safety  of  at  least  5 
at  the  maximum  allowable  working  pressure. 

208  The  diameter  of  a  screw  stay  shall  be  taken  at  the  bottom  of 
the  thread,  provided  this  is  the  least  diameter. 


CT9QOOOOOODOOOOOO 


FIG.  13     METHOD  OF  DETERMINING  NET  AREA  OF  SEGMENT  OF  A  HEAD 


,209  The  least  cross-sectional  area  of  a  stay  shall  be  taken  in  calcu- 
lating the  allowable  stress,  except  that  when  the  stays  are  welded  and 
have  a  larger  cross-sectional  area  at  the  weld  than  at  some  other  point, 
in  which  case  the  strength  at  the  weld  shall  be  computed  as  well  as  in 
the  solid  part  and  the  lower  value  used. 

210  Holes  for  screw  stays  shall  be  drilled  full  size  or  punched 
not  to  exceed  %  in.  less  than  full  diameter  of  the  hole  for  plates  over 
5/16  in.  in  thickness,  and  %  in.  less  than  the  full  diameter  of  the 
hole  for  plates  not  exceeding  5/16  in.  in  thickness,  and  then  drilled 
or  reamed  to  the  full  diameter.     The  holes  shall  be  tapped  fair  and 
true,  with  a  full  thread. 

211  The  ends  of  steel  stays  upset  for  threading,  shall  be  thor- 
oughly annealed. 

212  An  internal  cylindrical  furnace  which  requires  staying  shall 
be  stayed  as  a  flat  surface  as  indicated  in  Table  3. 


NEW  INSTALLATIONS,  TART  I,  SECTION  I,  POWER  BOILERS 


53 


2\>>  Staying  Segments  of  Heads.  A  segment  of  a  head  shall 
be  stayed  by  bead  to  bead,  through,  diagonal,  crowfoot  or  gusset  stays, 
except  that  a  horizontal  return  tubular  boiler  may  be  stayed  as  pro- 
vided in  Pars.  225  to  229. 

.214  Areas  of  Segments  of  Heads  to  be  Stayed.  The  area  of  a 
segment  of  a  head  to  be  stayed  shall  be  the  area  enclosed  by  lines  drawn 
3  in.  from  the  shell  and  2  in.  from  the  tubes,  as  shown  in  Figs.  13 
and  U. 

215  In  water  tube  boilers,  the  tubes  of  which  are  connected  to 
drum  heads,  the  area  to  be  stayed  shall  be  taken  as  the  total  area  of 
the  head  less  a  5  in.  annular  ring,  measured  from  the  inner  circum- 
ference of  the  drum  shell. 


ODOOOQ±OOOOOQ 

~op.o 


OQP 


FIG.  14     METHOD  OF  DETERMINING  NET  AREA  OF  IRREGULAR 
SEGMENT  OF  A  HEAD 


When  such  drum  heads  are  30  in.  or  less  in  diameter  and  the 
tube  plate  is  stiffened  by  flanged  ribs  or  gussets,  no  stays  need  be  used 
if  a  hydrostatic  test  to  destruction  of  a  boiler  or  unit  section  built  in 
accordance  with  the  construction,  shows  that  the  factor  of  safety  is  at 
least  5. 

216  In  a  fire  tube  boiler,  stays  shall  be  used  in  the  tube  sheets  if 
the  distances  between  the  edges  of  the  tube  holes  exceed  the  maximum 
pitch  of  staybolts  given  in  Table  3.  That  part  of  the  tube  sheet  which 
comes  between  the  tubes  and  the  shell,  need  not  be  stayed  when  the 
distance  from  the  inside  of  the  shell  to  the  outer  surface  of  the  tubes 
does  not  exceed  that  given  by  the  formula  in  Par.  199,  using  160  for 
the  value  of  C. 


54 


REPORT  OF  BOILER  CODE  COMMITTEE,  AM.SOC.M.K. 


217  The  net  area  to  be  stayed  in  a  segment  of  a  head  may  be  de- 
termined by  the  following  formula : 

4   (H—5}z    I  2   ( P     3} 

— -*(  — /->  r     K \    — 0.608  =  area  to  be  stayed,  sq.  in. 

where 

II  =  distance  from  tubes  to  shell,  in. 
R  —  radius  of  boiler  head,  in. 

218  When  the  portion  of  the  head  below  the  tubes  in  a  horizon- 
tal return  tubular  boiler  is  .provided  with  a  manhole  opening,  the 
flange  of  which  is  formed  from  the  solid  plate  and  turned  inward 
to  a  depth  of  not  less  than  three  times  the  thickness  of  the  head,  meas- 
ured from  the  outside,  the  area  to  be  stayed  as  indicated  in  Fig.  14, 
may  be  reduced  by  100  sq.  in.     The  surface  around  the  manhole  shall 
be  supported  by  through  stays  with  nuts  inside  and  outside  at  the  front 
head. 


TABLE  4 


MAXIMUM  ALLOWABLE  STRESSES  FOR  STAYS  AND 
STAYBOLTS 


Description  of  Stays 

Stresses,  Lb.  per  Sq.  In. 

For   Lengths   between 
Supports  not  Exceed- 
ing 120  Diameters 

For   Lengths   between 
Supports   Exceeding 
120  Diameters 

a  Unwelded  stays  less  than  twenty  diameters  long 
screwed  through  plates  with  ends  riveted  over.  . 
6  Unwelded  stays  and  unwelded  portions  of  welded 
stays,  except  as  specified  in  line  a  

7500 

9500 
6000 

8500 
6000 

c  Welded  portions  of  stays 

219  When  stay  rods  are  screwed  through  the  sheets  and  riveted 
over,  they  shall  be  supported  at  intervals  not  exceeding  6  ft.  In  boilers 
without  manholes,  stay  rods  over  6  ft.  in  length  may  be  screwed 
through  the  sheets  and  fitted  with  nuts  and  washers  on  the  outside. 

2.20  The  maximum  allowable  stress  per  square  inch  net  cross 
sectional  area  of  stays  and  staybolts  shall  be  as  given  in  Table  4. 

The  length  of  the  stay  between  supports  shall  be  measured  from 
the  inner  faces  of  the  stayed  plates.  The  stresses  are  based  on  tension 
only.  For  computing  stresses  in  diagonal  stays,  see  Pars.  2.21  and  222. 

2i21  Stresses  in  Diagonal  and  Gusset  Stays.  Multiply  the  area 
of  a  direct  stay  required  to  support  the  surface  by  the  slant  or  diagonal 


NEW  INSTALLATIONS,  TART  I,  SECTION  I,  POWER  BOILERS 


55 


length  of  the  stay;  divide  this  product  by  the  length  of  a  line  drawn 
at  right  angles  to  surface  supported  to  center  of  palm  of  diagonal  stay. 
The  quotient  will  be  the  required  area  of  the  diagonal  stay. 


A  = 


where 


A  =  sectional  area  of  diagonal  stay,  sq.  in. 
a  =  sectional  area  of  direct  stay,  sq.  in. 
Jj  =  length  of  diagonal  stay,  as  indicated  in  Fig.  15,  in. 
I  =  length  of  line  drawn  at  right  angles  to  boiler  head  or 

surface  supported  to  center  of  palm  of  diagonal  stay, 

as  indicated  in  Fig.  15,  in. 


FIG.  15 


MEASUREMENTS  FOR  DETERMINING  STRESSES  IN 
DIAGONAL  STAYS 


Given  diameter  of  direct  stay  =  1  in.,  a  =  0.7854,  L  =  60  in., 
I  =  48  in. ;  substituting  and  solving : 

A  =  -  -  =  0.981  sectional  area,  sq.  in. 

Diameter  =  1.11  in.  =  1%  in. 

22&  For  staying  segments  of  tube  sheets  such  as  in  horizontal 
return  tubular  boilers,  where  L  is  not  more  than  1.15  times  I  for  any 
brace,  the  stays  may  be  calculated  as  direct  stays,  allowing  90  per  cent 
of  the  stress  given  in  Table  4. 

223  Diameter  of  Pins  and  Area  of  Rivets  in  Brace.  The  'Sec- 
tional  area  of  pins  to  resist  double  shear  and  bending  when  secured  in 
crowfoot,  sling,  and  similar  stays  shall  be  at  least  eq'ial  to  three- 


56  REPORT  OF  BOILER  CODE  COMMITTEE,  AM.SOC.M.E. 

fourths  of  the  required  cross-sectional  area  of  the  brace.  The  com- 
bined cross  section  of  the  eye  at  the  sides  of  the  pin  shall  be  at  least 
25  per  cent  greater  than  the  required  cross-sectional  area  of  the  brace. 
The  cross.-sectional  area  of  the  rivets  attaching  a  brace  to  the 
shell  or  head  shall  be  not  less  than  one  and  one  quarter  times  the  re- 
quired sectional  area  of  the  brace.  Each  branch  of  a  crowfoot  shall 
be  designed  to  carry  two-thirds  of  the  total  load  on  the  brace.  The 
net  sectional  areas  through  the  sides  of  the  crowfeet,  tee  irons  or 
similar  fastenings  at  the  rivet  holes  shall  be  at  least  equal  to  the  re- 
quired rivet  section.  AU'rivet  holes  shall  be  drilled  and  burrs  removed, 
and  the  pins  shall  be  made  a  neat  fit. 


TABLE  5     SIZES  OF  ANGLES  REQUIRED  FOR  STAYING  SEGMENTS  OF  HEADS 
With  the  short  legs  of  the  angles  attached  to  the  head  of  the  boiler 


30"  Boiler 

34"  Boiler 

36"  Boiler 

Height 
of 

Angle 

Angle 

Angle 

Angle 

Angle 

Angle 

Angle 

Angle 

Angle 

Dimen- 

Segment, 

3"x2H" 

3^"x3" 

4"x3" 

3^"x3" 

4"x3" 

5"x3* 

4"x3" 

G"x3^" 

sion 

TV                '          "R 

A  in 

in  Fig.  16 

Thick- 

Thick- 

Thick- 

Thick- 

Thick- 

Thick- 

Thick- 

Thick- 

Thick- 

Fig. 16 

ness, 

ness, 

ness, 

ness, 

ness, 

ness, 

ness, 

ness, 

ness, 

inches 

inches 

inches 

inches 

inches 

inches 

inches 

inches 

inches 

10 

H 

A 

A 

.  . 









. 

6^ 

11 

A 

N 

A 

A 

A 

A 

— 

— 

— 

7 

12 

A 

A 

N 

Yi 

A 

A 

A 

A 

— 

ly* 

13 

— 

ft 

A 

H 

H 

A 

A 

% 

— 

8 

14 

— 

— 

Vi 

— 

N 

iHI 

% 

A 

y* 

8>£ 

15 

— 

— 

— 

— 

— 

H 

H 

Yz 

H 

9 

16 

— 

— 

— 

— 

— 

— 

— 

H 

A 

9^ 

\ 

224  Gusset  stays  when  constructed  of  triangular  right-angled  web 
plates  secured  to  single  or  double  angle  •  bars  along  the  two  sides 
at  right  angles  shall  have  a  cross-sectional  area  (in  a  plane  at  right 
angles  to  the  longest  side  and  passing  through  the  intersection  of  the 
two  shorter  sides)  not  less  than  10  per  cent  greater  than  would  be 
required  for  a  diagonal  stay  to  support  the  same  surface,  figured  by  the 
formula  in  Par.  22.\,  assuming  the  diagonal  stay  is  at  the  same  angle 
as  the  longest  side  of  the  gusset  plate. 

2.25  Staying  of  Upper  Segments  of  Tube  Heads  by  Steel  Angles. 
When  the  shell  of  a. boiler  does  not  exceed  36  in.  in  diameter  and  is 
designed  for  a  maximum  allowable  working  pressure  not  exceeding  100 
Ib.  per  sq,  in.,  the  segment  of  heads  above  the  tubes  may  be  stayed  by 
steel  angles  as  specified  in  Table  5  and  Fig.  16,  except  that  angles  of 


NEW  INSTALLATIONS,  PART  I,  SECTION  I,  TOWER  ROILERS 


f.7 


equal  thickness  and  greater  depth  of  outstanding  leg,  or  of  greater 
thickness  and  the  same  depth  of  outstanding  leg,  may  he  substituted  for 
those  specified.  The  legs  attached  to  the  heads  may  vary  in  depth 
!/2  in.  above  or  below  the  dimensions  specified  in  Table  5. 

226  When  this  form  of  bracing  is  to  be  placed  on  a  boiler,  the 
diameter  of  which  is  intermediate  to  or  below  the  diameters  given  in 
Table  5,  the  tabular  values  for  the  next  higher  diameter  shall  govern. 
Rivets  of  the  same  diameter  as  used  in  the  longitudinal  seams  of  the 
boiler  shall  be  used  to  attach  the  angles  to  the  head  and  to  connect 
the  outstanding  legs. 


FIG.  16     STAYING  OF  HEAD  WITH  STEEL  ANGLES  IN  TUBULAR  BOILER 


,2i27  The  rivets  attaching  angles  to  heads  shall  be  spaced  not 
over  4  in.  apart.  The  centers  of  the  end  rivets  shall  be  not  over  3  in. 
from  the  ends  of  the  angle.  The  rivets  through  the  outstanding  legs 
shall  be  spaced  not  over  8  in.  apart ;  the  centers  of  the  end  rivets  shall 
be  not  more  than  4  in.  from  the  ends  of  the  angles.  The  ends  of  the 
angles  shall  be  considered  those  of  the  outstanding  legs  and  the  lengths 
shall  be  such  that  their  ends  overlap  a  circle  3  in.  inside  the  inner 
surface  of  the  shell  as  shown  in  Fig.  16. 

228  The  distance  from  the  center  of  the  angles  to  the  shell  of 
the  boiler,  marked  A  in  Fig.  16,  shall  not  exceed  the  values  given  in 
Table  5,  but  in  no  case  shall  the  leg  attached  to  the  head  on  the  lower 
angle  come  closer  than  2  in.  to  the  top  of  the  tubes. 


58  REPORT  OF  BOILER  CODE  COMMITTEE,  AM.SOC.M.E. 

2(29  When  segments  are  beyond  the  range  specified  in  Table  5, 
the  heads  shall  be  braced  or  stayed  in  accordance  with  the  requirements 
in  these  Eules. 

2.30  Crown  Bars  and  Girder  Stays.  'Crown  bars  and  girder  stays 
for  tops  of  combustion  chambers  and  back  connections,  or  wherever 
used,  shall  be  proportioned  to  conform  to  the  following  formula  : 


Maximum  allowable  working  pressure  =   /w__m  \/  ny  UA 

where 

W  —  extreme  distance  between  supports,  in. 
P  —  pitch  of  supporting  bolts,  in. 

D  =  distance  between  girders  from  center  to  center,  in. 
d  =  depth  of  girder,  in. 
T  =  thickness  of  girder,  in. 

C  =  7000  when  the  girder  is  fitted  with  one  supporting  bolt 
C  =  10,000  when  the  girder  is  fitted  with  two  or  three  sup- 

porting bolts 
C  =  11,000  when  the  girder  is  fitted  with  four  or  five  sup- 

porting bolts 
C  =  11,500  when  the  girder  is  fitted  with  six  or  seven  sup- 

porting bolts 
C  =  12,000  when  the  girder  is  fitted  with  eight  or  more  sup- 

porting bolts 

Example:  Given  W  =  34  in.,  P  =  7.5  in.,  D  --  --  7.75  in., 
d  ==  7.5  in.,  T  ==  2  in.;  three  stays  per  girder,  C  =  10,000;  then 
substituting  in  formula  : 

Maximum  allowable  working  pressure  = 

10,000X7.5X7.5X2 

(34-7.5)  X7.75X34  =  -  16L1  lb'  Pcr  **'  m' 

&31  Maximum  Alloicalle  Working  Pressure  on  Truncated  Cones. 
Upper  combustion  chambers  or  vertical  submerged  tubular  boilers 
made  in  the  shape  of  a  frustum  of  a  cone  when  not  over  3>8  in.  diam- 
eter at  the  large  end,  may  be  used  without  stays  if  figured  by  the 
rule  for  plain  cylindrical  furnaces  (Par.  239)  making  D  in  the  for- 
mula equal  to  the  diameter  at  the  large  end.  When  over  38  in.  in 
diameter,  that  portion  over  30  -in.  in  diameter  shall  be  fully  supported 
by  staybolts  or  gussets  to  conform  to  the  provisions  for  the  staying  of 
flat  surfaces. 

232     Stay   Tubes.     When  stay  tubes  are  used  in  multitubular 


NEW  INSTALLATIONS,  PART  I,  SECTION  I,  POWER  BOILERS  59 

boilers  to  give  support  to  the  tube  plates,  the  sectional  area  of  such 
stay  tubes  may  be  determined  as  follows: 

Total  section  of  stay  tubes,  sq.  in.  =         — -^ * 

where 

A  =  area  of  that  portion  of   the  tube  plate   containing  th'j 

tubes,  sq.  in. 

a  =  aggregate  area  of  holes  in  the  tube  plate,  sq.  in. 
P  =  maximum  allowable  working  pressure,  Ib.  per  sq.  in. 
T  =  working  tensile  stress  allowed  in  the  tubes,  not  to  exceed 

7000  Ib.  per  sq.  in. 

,233     The  pitch  of  stay  tubes  shall  conform  to  the  formula  given 
in  Par.  199,  using  the  values  of  C  as  given  in  Table  6. 

TABLE  0.  VALUES  OF  C  FOR  DETERMINING  PITCH  OF  STAY  TUBES. 


Pitch  of  Stay  Tubes  in  the  Bounding  Rows 

When  tubes 
have  no  Nuts 
Outside  of  Plates 

When  tubes 
are  Fitted  with 
Nuts  Outside 
of  Plates 

Where  there  are  two  plain  tubes  between  each  stay  tube  .... 
Where  there  is  one  plain  tube  between  each  stay  tube  
Where  every  tube  in  the  bounding  rows  is  a  stay  tube  and 
each  alternate  tube  has  a  nut  

120 
140 

130 
150 

170 

When  the  ends  of  tubes  are  not  shielded  from  the  action  of  flame  or 
radiant  heat,  the  values  of  C  shall  be  reduced  20  per  cent.  The  tubes 
shall  project  about  !/4  in.  at  each  end  and  be  slightly  flared.  Stay 
tubes  when  threaded  shall  not  be  less  than  3/16  in.  thick  at  bottom  of 
thread ;  nuts  on  stay  tubes  are  not  advised.  For  a  nest  of  tubes  C  shall 
be  taken  as  140  and  8  as  the  mean  pitch  of  stay  tubes.  For  spaces  be- 
tween nests  of  tubes  8  shall  be  taken  as  the  horizontal  distance  from 
center  to  center  of  the  bounding  rows  of  tubes  and  C  as  given  in 
Table  6. 

TUBE    SHEETS    OF    COMBUSTION    CHAMBERS 

234  The  maximum  allowable  working  pressure  on  a  tube  sheet 
of  a  combustion  chamber,  where  the  crown  sheet  is  not  suspended  from 
the  shell  of  the  boiler,  shall  be  determined  by  the  following  formula : 

(D—d)   7X27,000 

r''  WXD 


60  REPORT  01^  TOILER  CODE  COMMITTEE.  AM.SOC.M.E. 

where 

P  =  maximum  allowable  working  pressure,  lb.  per  sq.  in. 
D  =  least  horizontal  distance  between  tube  centers,  in. 
d  =  inside  diameter  of  tubes,  in. 
T  =  thickness  of  tube  plate,  in. 
W  =  distance  from  tube  sheet  to  opposite  combustion  chamber 

sheet,  in. 

Example:  Required  the  working  pressure  of  a  tube  sheet  sup- 
porting a  crown  sheet  braced  by  crown  bars.  Horizontal  distance 
between  centers,  4%  in.;  inside  diameter  of  tubes,  2.782  in. ;  thickness 
of  tube  sheets,  11/16  in.;  distance  from  tube  sheet  to  opposite  com- 
bustion chamber  sheet,  34^4  in.,  measured  from  outside  of  tube  plate 
to  outside  of  back  plate;  material,  steel.  .Substituting  and  solving: 
p  (4.125— 2.782)  X0.6875X27,000 

34.25X4,125  1  ' 6  lb'  ^  ^  m' 

235     Sling  stays  may  be  used  in  place  of  girders  in  all  cases  cov- 
ered in  Par.  2,34,  provided,  however,  that  when  such  sling  stays  are 


FIG.  17     PROPER  LOCATION  OF  STAYBOLTS  ADJACENT  TO  LONGITUDINAL 
JOINT  IN  FURNACE  SHEET 

used,  girders  or  screw  stays  of  the  same  sectional  area  shall  be  used  for 
securing  the  bottom  of  the  combustion  chamber  to  the  boiler  shell. 

23*6  When  girders  are  dispensed  with  and  the  top  and  bottom 
of  combustion  chambers  are  secured  by  sling  stays  or  braces,  the  sec- 
tional area  of  such  stays  shall  conform  with  the  requirements  of  rules 
for  stays  and  stayed  surfaces. 

237  Furnaces  of  Vertical  Boilers.     In  a  vertical  fire-tube  boiler 
the  furnace  length,  for  the  purpose  of  calculating  its  strength  and 
spacing  staybolts  over  its  surface,  shall  be  measured  from  the  center 
of  rivets  in  the  bottom  of  the  water-leg  to  the  center  of  rivets  iri  the 
flange  of  the  lower  tube  sheet. 

238  When  the  longitudinal  joint  of  the  furnace  sheet  of  a  vertical 
fire-tube  boiler  is  of  lap-riveted  construction  and  staybolted,  a  stay- 
bolt  in  each  circular  row  shall  be  located  near  the  longitudinal  joint, 
as  shown  in  Fig.  17. 


NEW  INSTALLATIONS,  TART  I,  SECTION  I,  TOWER  BOILERS  61 

239  Plain  Circular  Furnaces.  The  maximum  allowable  working 
pressure  for  unstayed,  riveted,  seamless  or  lap  welded  furnaces,  where 
the  length  does  not  exceed  6  times  the  diameter  and  where  the  thick- 
ness is  at  least  5/16  in.  shall  he  determined  by  one  or  the  other  of  the 
following  formulae: 

a  Where  the  length  does  not  exceed  120  times  the  thickness  of 
the  plate 


&  Where  the  length  exceeds  120  times  the  thickness  of  the  plate 
P  __  4250X?'2 

:  LXD 

where 

P  =  maximum  allowable  working  pressure,  Ib.  per  sq.  in. 

D  =  outside  diameter  of  furnace,  in. 

L  =  length  of  furnace,  in. 

T  =  thickness  of  furnace  walls,  in  sixteenths  of  an  inch. 
Where  the  furnaces  have  riveted  longitudinal  joints  no  deduction 
need  be  made  for  the  joint  provided  the  efficiency  of  the  joint  is  greater 
than  PXD  divided  by  1,250X^. 

Example.  Given  a  furnace  26  in.  in  diameter,  94  in.  long  and 
1/2  in.  thick.  The  length  exceeds  120  times  the  thickness  of  the  plate, 
hence  the  formula  (ft)  should  be  used.  Substituting  the  values  in 
this  formula  : 

4250X8X8 
P'          94X26          =  HI  lb-  per  sq.  in. 

240  A  plain  cylindrical  furnace  exceeding  38  in.  in  diameter  shall 
be  stayed  in  accordance  with  the  rules  governing  flat  surfaces. 

241  Circular  Flues.     The  maximum  allowable  working  pressure 
for  seamless  or  welded  flues  more  than  5  in.  in  diameter  and  up  to  and 
including  18  in.  in  diameter  shall  be  determined  by  one  or  the  other 
of  the  following  formulae  : 

a  Where  the  thickness  of  the  wall  is  less  than  0.023  times  the 
diameter 

1  0,000, 


D* 

&  Where  the  thickness  of  the  wall  is  greater  than  0.0;23  times 
the  diameter 

p=  17,300X7: 


G2  REPORT  OF  BOILER  CODE  COMMITTEE,  AM.SOC.M.E. 

where 

P  —  maximum  allowable  working  pressure,  Ib.  per  sq.  in. 

D  —  outside  diameter  of  flue,  in. 

T  —  thickness  of  wall  of  flue,  in. 
c  The  above  formulae  may  be  applied  to  riveted  flues  of  the 

sizes  specified  provided  the  sections  are  not  over  3  ft.  in 

length  and  provided  the  efficiency  of  the  joint  is  greater 

than  PX#  divided  by  20,OOOXZ\ 

Example.  Given  a  flue  14  in.  in  diameter  and  5/16  in.  thick. 
The  thickness  of  the  wall  is  less  than  0.023  times  the  diameter ;  hence 
the  formula  (a)  should  be  used.  Substituting  the  values  in  this 
formula : 

10,000,000X5/16X5/16X5/16 
P=  14X14X14  =  HO  Ib.  per  sq.  in. 

242  A  damson  Type.  "Wlien  plain  horizontal  flues  are  made  in 
sections  not  less  than  18  in.  in  length,  and  not  less  than  5/16  in.  thick: 

a  They  shall  be  flanged  with  a  radius  measured  on  the  fire  side, 
of  not  less  than  three  times  the  thickness  of  the  plate,  and  the  flat 
portion  of  the  flange  outside  of  the  radius  shall  be  at  least  three  times 
the  diameter  of  the  rivet  holes. 

7;  The  distance  from  the  edge  of  the  rivet  holes  to  the  edge  of  the 
flange  shall  be  not  less  than  the  diameter  of  the  rivet  hole,  and  the 
diameter  of  the  rivets  before  driving  shall  be  at  least  y±  in.  larger  than 
the  thickness  of  the  plate. 

c  The  depth  of  the  Adamson  ring  between  the  flanges  shall  be  not 
less  than  three  times  the  diameter  of  the  rivet  holes,  and  the  ring  shall 
be  substantially  riveted  to  the  flanges.  The  fire  edge  of  the  ring  shall 
terminate  at  or  about  the  point  of  tangency  to  the  curve  of  the  flange, 
and  the  thickness  of  the  ring  shall  be  not  less  than  y2  in. 

The  maximum  allowable  working  pressure  shall  be  determined  by 
the  following  formula : 

P=   ^  |  (18. 

where 

P  =  maximum  allowable  working  pressure,  Ib.  per  sq.  in. 

D  =  outside  diameter  of  furnace,  in. 

L  =  length  of  furnace  section,  in. 

T  ==  thickness  of  plate,  in  sixteenths  of  an  inch. 
Example.     Given  a  furnace  44  in.  in  diameter,  48  in.  in  length, 
and  y2  in.  thick.    Substituting  values  in  formula : 


NEW  INSTALLATIONS,  PART  I,   SECTION  I,  TOWER  BOILERS 

P=  5M_  |  (18.75X8)  —  (1.03X48) 

=  1.309  (150—49.44)  =  131  Ib.  per  sq.  in. 

243  The  maximum  allowable  working  pressure  on  corrugated 
furnaces,  such  as  the  Leeds  suspension  bulb,  Mori  son,  Fox,  Purves,  or 
Brown,  having  plain  portions  at  the  ends  not  exceeding  9  in.  in  length 
(except  flues  especially  provided  for)  when  new  and  practically  circu- 
lar, shall  be  computed  as  follows  : 


P_         . 

D 

where 

P  =  maximum  allowable  working  pressure,  Ib.  per  sq.  in. 

T  =  thickness,  in.  —  not  less  than  5/16  in.  for  Leeds,  Morison, 
Fox  and  Brown,  and  not  less  than  7/16  in.  for  Purves 
and  other  furnaces  corrugated  by  sections  not  over  18 
in.  long. 

D  =  mean  diameter,  in. 

C  =  17,300,  a  constant  for  Leeds  furnaces,  when  corrugations 
are  not  more  than  8  in.  from  center  to  center  and  not 
less  than  21/4  in.  deep. 

C  =  15,600,  a  constant  for  Morison  furnaces,  when  corruga- 
tions are  not  less  than  8  in.  from  center  to  center  and 
the  radius  of  the  outer  corrugations  is  not  more  than 
one  half  that  of  the  suspension  curve. 

C  =  14,000,  a  constant  for  Fox  Furnaces,  when  corrugations 
are  not  more  than  8  in.  from  center  to  center  and  not 
less  than  1%  in.  deep. 

C  =  14,000,  a  constant  for  Purves  furnaces  when  rib  projec- 
tions are  not  more  than  9  in.  from  center  to  center  and 
not  less  than  1%  in.  deep. 

C  =  14,000,  a  constant  for  Brown  Furnaces,  when  corrugations 
are  not  more  than  9  in.  from  center  to  center  and  not 
less  than  1%  in.  deep. 

C  =  10,000,  a  constant  for  furnaces  corrugated  by  sections  not 
more  than  18  in.  from  center  to  center  and  not  less 
than  21/0  in.  deep,  measured  from  the  least  inside  to 
the  greatest  outside  diameter  of  the  corrugations,  and 
having  the  ends  fitted  one  into  the  other  and  substan- 
tially riveted  together,  provided  that  the  plain  parts 
at  the  ends  do  not  exceed  12  in.  in  length. 


64  REPORT  OP  BOILER  COPE  COMMITTEE,  AM.SOO.M.E. 

Ill  calculating  the  mean  diameter  of  the  Morison  furnace,  the  least 
inside  diameter  plus  2  in.,  may  he  taken  as  the  mean  diameter. 

244  The  thickness  of  a  corrugated  or  ribbed  furnace  shall  be  as- 
certained by  actual  measurement.    The  furnace  shall  be  drilled  for  a 
!/4-in.  pipe  tap  and  fitted  with  a  screw -plug  that  can  be  removed  for 
the  purpose  of  measurement.   For  the  Brown  and  Purves  furnaces,  the 
holes  shall  be  in  the  center  of  the  second  flat;  for  the  Morison,  Fox 
and  other  similar  types,  in  the  center  of  the  top  corrugation,  at  least 
as  far  in  as  the  fourth  corrugation  from  the  end  of  the  furnace. 

245  Cast  Iron  Headers.     The  pressure  allowed  on  a  water-tube 
boiler,  the  tubes  of  which  are  secured  to  cast-iron  or  malleable-iron 
headers,  shall  not  exceed  160  Ib.  per  sq.  in.    The  form  and  size  of  the 
internal  cross  section  of  a  cast-iron  or  malleable-iron  header  at  any 
point  shall  be  such  that  it  will  fall  within  a  6  in.  by  7  in.  rectangle. 

246  The  cast-iron  used  for  the  headers  of  water-tube  boilers  shall 
conform  with  the  Specifications  for  Gray-iron  Castings  given  in  Pars. 
95  to  110,  the  header  to  be  arbitrarily  classified  as  a  "medium  casting" 
as  to  physical  properties  and  tests,  and  as  a  "light  casting"  as  to 
chemical  properties. 

247  A  cast-iron  header  when  tested  to  destruction,  shall  withstand 
a  hydrostatic  pressure  of  at  least  1200  Ib.  per  sq.  in.     A  hydrostatic 
test  at  400  Ib.  per  sq.  in.  gage  pressure  shall  be  made  on  all  new 
headers  with  tubes  attached. 

TUBES 

248  Tube  Holes  and  Ends.     Tube  holes  shall  be  drilled  full  size 
from  the  solid  plate,  or  they  may  be  punched  at  least  l/2  in.  smaller 
in  diameter  than  full  size,  and  then  drilled,  reamed  or  finished  full 
size  with  a  rotating  cutter. 

249  The  sharp  edges  of  tube  holes  shall  be  taken  off  on  both  sides 
of  the  plate  with  a  file  or  other  tool. 

250  A  fire-tube  boiler  shall  have  the  ends  of  the  tubes  substan- 
tially rolled  and  beaded,  or  welded  at  the  firebox  or  combustion  cham- 
ber end. 

251  The  ends  of  all  tubes,  suspension  tubes  and  nipples  shall  be 
flared  not  less  than  %  in.  over  the  diameter  of  the  tube  hole  on  all 
water-tube  boilers  and  superheaters/ or  they  may  be  beaded. 

252  The  ends  of  all  tubes,  suspension  tubes  and  nipples  of  water- 
tube  boilers  and  superheaters  shall  project  through  the  tube  sheets  or 
headers  not  less  than  %  in.  nor  more  than  y2  in.  before  flaring. 


NEW  INSTALLATIONS,  TART  I,  SECTION  I,  POWER  BOILERS  65 

RIVETING 

253  Riveting.     Rivet  holes,  except  for  attaching  stays  or  angle 
bars  to  heads,  shall  be  drilled  full  size  with  plates, 'butt  straps  and 
heads  bolted  in  position ;  or  they  may  be  punched  not  to  exceed  %  in. 
less  than  full  diameter  for  plates  over  5/16  in.  in  thickness,  and  %  in. 
less  than  full  diameter  for  plates  not  exceeding  5/16  in.  in  thickness, 
and  then  drilled  or  reamed  to  full  diameter  with  plates,  butt  straps 
and  heads  bolted  in  position. 

254  After  drilling  rivet  holes,  the  plates  and  butt  straps  shall  be 
separated  and  the  burrs  removed. 

255  Rivets.     Rivets  shall  be  of  sufficient  length  to  completely  fill 
the  rivet  holes  and  form  heads  at  least  equal  in  strength  to  the  bodies 
of  the  rivets. 

256  Rivets  shall  be  machine  driven  wherever  possible,  with  suffi- 
cient pressure  to  fill  the  rivet  holes,  and  shall  be  allowed  to  cool  and 
shrink  under  pressure. 

CALKING 

2-57  Calking.  The  calking  edges  of  plates,  butt  straps  and  heads 
shall  be  beveled.  Every  portion  of  the  calking  edges  of  plates,  butt 
straps  and  heads  shall  be  planed,  milled  or  chipped  to  a  depth  of  not 
less  than  %  in.  Calking  shall  be  done  with  a  round-nosed  tool. 

MANHOLES 

258  Manholes.     An  elliptical  manhole  opening  shall  be  not  less 
than  11  X  15  in.  or  10  X  16  in.  in  size.    A  circular  manhole  opening 
shall  be  not  less  than  15  in.  in  diameter. 

259  A  manhole  reinforcing  ring  when  used,  shall  be  of  steel  or 
wrought-iron,  and  shall  be  at  least  as  thick  as  the  shell  plate. 

260  Manhole  frames  on  shells  or  drums  when  used,  shall  have  the 
proper  curvature,  and  on  boilers  over  48  in.  in  diameter  shall  be  riveted 
to  the  shell  or  drum  with  two  rows  of  rivets,  which  may  be  pitched  as 
shown  in  Fig.  18.     The  strength  of  the  rivets  in  shear  on  manhole 
frames  and  reinforcing  rings  shall  be  at  least  equal  to  the  tensile 
strength  of  that  part  of  the  shell  plate  removed,  on  a  line  parallel  to 
the  axis  of  the  shell,  through  the  center  of  the  manhole,  or  other 
opening. 


66 


REPORT  OF  BOILER  CODE  COMMITTEE,  AM.SOC.M.E. 


2-61  The  proportions  of  manhole  frames  and  other  reinforcing 
rings  to  conform  to  the  above  specifications  may  be  determined  by  the 
use  of  the  following  formulae,  which  are  based  011  the  assumption  that 
the  rings  shall  have  the  same  tensile  strength  per  square  inch  of  sec- 
tion as,  and  be  of  not  less  thickness  than,  the  shell  plate  removed. 


For  a  single-riveted  ring:    W  =  TT\/ 


For  a  double-riveted  ring:   T7  =  "nTTr 


FIG.  18     METHOD  OF  RIVETING  MANHOLE  FRAMES  TO  SHELLS  OR 
DRUMS  WITH  Two  Eows  OF  RIVETS 


For  two  single-riveted  rings :    W  =  ~rrrr~ 

7V/ 
For  two  double-riveted  rings :   W  =          *" --{-2d 


Where 

W  =  least  width  of  reinforcing  ring,  in. 
t^  =  thickness  of  shell  plate,  in. 
d  —  diameter  of  rivet  when  driven,  in. 
t  =  thickness  of  reinforcing  ring — not  less  than  thickness  of 

the  shell  plate,  in. 

T  =  tensile  strength  of  the  ring,  Ib.  per  sq.  in.  of  section 
a  =  net  section  of  one  side  of  the  ring  or  rings,  sq.  in. 
S  —  shearing  strength  of  rivet,  Ib.  per  sq.  in.  of  section  (see 
Par.  16) 


NEW  INSTALLATIONS,  PART  I,  SECTION  I,  POWER  BOILERS  67 

Z  =  length  of  opening  in  shell  in  direction  parallel  to  axis  of 

shell,  in. 

N  =  number  of  rivets 
To  find  the  number  of  rivets  for  a  single  or  double  reinforcing  ring: 


SXd2 

,2i6»2     Manhole  plates  shall  be  of  wrought  steel  or  shall  be  steel 
castings. 

263  The  minimum  width  of  bearing  surface,  for  a  gasket  on  a 
manhole  opening  shall  be  ]/i>  in.     ^°  gasket  for  use  on  a  manhole  or 
handhole  of  any  boiler  shall  have  a  thickness  greater  than  1/4  in. 

264  A  manhole  shall  be  located  in  the  front  head,  below  the 
tubes,  of  a  horizontal  return  tubular  boiler  48  in.  or  over  in  diameter. 
Smaller  boilers  shall  have  either  a  manhole  or  a  handhole  below  the 
tubes.    There  shall  be  a  manhole  in  the  upper  part  of  the  shell  or  head 
of  a  fire-tube  boiler  over  40  in.  in  diameter,  except  a  vertical  fire-tube 
boiler,  or  except  on  internally  fired  boilers  not  over  48  in.  in  diameter. 
The  manhole  may  be  placed  in  the  head  of  the  dome.    Smaller  boilers 
shall  have  either  a  manhole  or  a  handhole  above  the  tubes. 


WASHOUT  HOLES 

265  A  traction,  portable  or  stationary  boiler  of  the  locomotive 
type  shall  have  not  less  than  six  handholes,  or  washout  plugs,  located 
as  follows:  one  in  the  rear  head  below  the  tubes;  one  in  the  front 
head  at  or  about  the  line  of  the  arown  sheet ;  four  in  the  lower  part  of 
the  waterleg;  also,  where  possible,  one  near  the  throat  sheet. 

,266  A  vertical  fire- tube  boiler,  except  the  boiler  of  a  steam  fire- 
engine,  shall  have  not  less  than  seven  handholes,  located  as  f  ollows : 
three  in  the  shell  at  or  about  the  line  of  the  crown  sheet;  one  in  the 
shell  at  or  about  the  line  of  the  fusible  plug  when  used ;  three  in  the 
shell  at  the  lower  part  of  the  waterleg.  A  vertical  fire-tube  boiler,  sub- 
merged tube  type,  shall  have  two  or  more  handholes  in  the  shell,  in 
line  with  the  upper  tube  sheet. 

267  A  vertical  fire- tube  boiler  of  a  steam  fire-engine  shall  have  at 
least  three  brass  washout  plugs  of  not  less  than  1-in.  iron  pipe  size, 
screwed  into  the  shell  and  located  as  follows :  one  at  or  about  the  line 
of  the  crown  sheet  •  two  at  the  lower  part  of  the  waterleg. 


68  REPORT  OF  BOILER  CODE  COMMITTEE,  AM.SOC.M.E. 

THREADED  OPENINGS 

268  Threaded  Openings.  An  opening  in  a  boiler  for  a  threaded 
pipe  connection  1  in.  in  diameter  or  over  shall  have  not  less  than  the 
number  of  threads  given  in  Table  7. 


TABLE  7    MINIMUM  NUMBER  OF  PIPE  THREADS  FOR  CONNECTIONS  TO 

BOILERS 


Si/o  of  pipe   connec- 
tion, in  

1  and  \% 

\Yi  and  2 

2*4  to  4 

tK  to  fi 

7  and  8 

9  and  10 

12 

Number    of    threads 
per  in  

ny2 

UK 

8 

8 

8 

8 

8 

Minimum  number  of 

4 

5 

7 

8 

10 

12 

13 

threads  required  in 
opening 

Minimum     thickness 

0.348 

0.435 

O.S75 

1 

1.25 

1.5 

1.625 

of  material  re- 

quired to  tfive  above 
number  of  threads, 

If  the  thickness  of  the  material  in  the  boiler  is  not  sufficient  to  give 
such  number  of  threads,  there  shall  be  a  pressed  steel  flange,  bronze 
composition  flange,  steel-cast  flange  or  steel  plate,  so  as  to  give  the  re- 
quired number  of  threads,  constructed  and  riveted  to  the  boiler  in  ac- 
cordance with  methods  given  in  Par.  261.  A  steam  main  or  safety 
valve  opening  may  be  fitted  with  either  a  steel  cast,  wrought-steel  or 
bronze  composition  nozzle.  A  feed-pipe  connection  may  be  fitted  with 
a  brass  or  steel  boiler  bushing. 

• 
SAFETY  VALVES 


269  Safety  Valve  Requirements.     Each  boiler  shall  have  two  or 
more  safety  valves,  except  a  boiler  for  which  one  safety  valve  3-in.  size 
or  smaller  is  required  by  these  Eules. 

270  The  safety  valve  capacity  for  each  boiler  shall  be  such  that 
the  safety  valve  or  valves  will  discharge  all  the  steam  that  can  be 
generated  by  the  boiler  without  allowing  the  pressure  to  rise  more 
than  six  per  cent  above  the  maximum  allowable  working  pressure,  or 
more  than  six  per  cent  above  the  highest  pressure  to  which  any  valve 
is  set. 

271  One  or  more  safety  valves  on  every  boiler  shall  be  set  at  or 
below  the  maximum   allowable  working  pressure.      The   remaining 


NEW  INSTALLATIONS,  PART  I,   SECTION  I,  POWER  BOILERS  09 

valves  may  be  set  within  a  range  of  three  per  cent  above  the  maximum 
allowable  working  pressure,  but  the  range  of  setting  of  all  of  the 
valves  on  a  boiler  shall  not  exceed  ten  per  cent  of  the  highest  pressure 
to  which  any  valve  is  set. 

27,2  .Safety  valves  shall  be  of  the  direct  spring  loaded  pop  type 
with  seat  and  bearing  surface  of  the  disc  either  inclined  at  an  angle 
of  about  45  deg.  or  flat  at  an  angle  of  about  90  deg.  to  the  center 
line  of  the  spindle.  The  vertical  lift  of  the  valve  disc  measured 
immediately  after  the  sudden  lift  due  to  the  pop  may  be  made  any 
amount  desired  up  to  a  maximum  of  0.15  in.  irrespective  of  the  size 
of  the  valve.  The  nominal  diameter  measured  at  the  inner  edge  of 
the  valve  seat  shall  be  not  less  than  1  in.  or  more  than  4%  in. 

273  Each  safety  valve  shall  have  plainly  stamped  or  cast  on  the 
body: 

a  The  name  or  identifying  trade-mark  of  the  manufacturer 

I  The  nominal  diameter  with  the  words  "Bevel  Seat"  or  "Flat 
Seat" 

c  The  steam  pressure  at  which  it  is  set  to  blow 

d  The  lift  of  the  valve  disc  from  its  seat,  measured  immedi- 
ately after  the  sudden  lift  due  to  the  pop 

e  The  weight  of  steam  discharged  in  pounds  per  hour  at  the 
pressure  for  which  it  is  set  to  blow. 

274  The  minimum  capacity  of  a  safety  valve  or  valves  to  be 
placed  on  a  boiler  shall  be  determined  on  the  basis  of  6  Ib.  of  steam 
per  hour  per  sq.  ft.  of  boiler  heating  surface  for  water  tube  boilers, 
and  5  Ib.  for  all  other  types  of  power  boilers,  and  upon  the  relieving 
capacity  marked  on  the  valves  by  the  manufacturer,  provided  such 
marked  relieving  capacity  does  not  exceed  that  given  in  Table  8.    In 
case  the  relieving  capacity  marked  on  the  valve  or  valves  exceeds  the 
maximum  given  in  Table  8,  the  minimum  safety  valve  capacity  shall 
be  determined  on  the  basis  of  the  maximum  relieving  capacity  given  in 
Table  8  for  the  particular  size  of  valve  and  working  pressure  for 
which  it  was  constructed.     The  heating  surface  shall  be  computed 
for  that  side  of  the  boiler  surface  exposed  to  the  products  of  com- 
bustion, exclusive  of  the  superheating  surface.     In  computing  the 
heating  surface  for  this  purpose  only  the  tubes,  shells,  tube  sheets 
and  the  projected  area  of  headers  need  be  considered. 


TABLE  8     DISCHARGE  CAPACITIES  FOR  DIRECT  SPRING-LOADED  POP  SAFETY  VALVES, 

WITH  45  DEG.  BEVEL  SEATS 


Gage 
Pres., 
Lb.  per 
Pq.  In. 

Diameter,  1  In. 

Diameter,  1)£  In. 

Diameter,  l}/2  In. 

Min. 

Int. 

Max. 

Min. 

Int. 

Max. 

Min. 

Iiit. 

Max. 

15 

Lift,  in  

0.02 

0.04 

0.05 

0.03 

0.04 

0.05 

0.03 

0.05 

0.06 

CH  

95,500 

191,000 

238,900 

179,200 

238,800 

293,500 

214,900 

358,300 

429,900 

Lb.  hr.  . 

65 

131 

163 

122 

163 

203 

146 

245 

293 

25 

Lift,  in.... 

0.02 

0.04 

0.05 

0.03 

0.04 

0.05 

0.03 

0.05 

0.06 

CH 

127,700 

255,400 

319,300 

239,500 

319,300 

399,100 

287,400 

478,900 

574,700 

Lb.  hr.  . 

87 

174 

218 

164 

218 

272 

196 

326 

39L 

50 

Lift,  in  .... 

0.02 

0.04 

0.05 

0.03 

0.04 

0.05 

0.03 

0.05 

0.06 

CH  

208,200 

416,400 

520,400 

390,300 

520,400 

650,500 

468,300 

780,600 

936,600 

Lb.  hr.  . 

142 

284 

354 

266 

354 

441 

320 

532 

68! 

75 

Lift,  in  

0.02 

0.04 

0.05 

0.03 

0.04 

0.05 

0.03 

0.05 

0.06 

CH 

288,600 

577,200 

721,400 

541,100 

721,400 

901.80C 

649,300 

1,082,000 

1,299,000 

Lb.  hr.  . 

197 

393 

492 

369 

492 

615 

443 

738 

88( 

100 

Lift,  in  .... 

0.02 

0'.04 

0.05 

0.03 

0.04 

0.05 

0.03 

0.05 

0.06 

CH  

369,000 

738,000 

922,500 

691,900 

922,500 

1,153,000 

830,300 

1,384,000 

1,661,000 

Lb.  hr  

252 

503 

629 

472 

629 

786 

566 

944 

1133 

125 

Lift,  in  

0.02 

0.04 

0.05 

0.03 

0.04 

0.05 

0.03 

0.05 

0.06 

CH 

449,400 

898,900 

1,124,000 

842,700 

1,124,000 

1,404,000 

1,011,000 

1,685,000 

2,022,000 

Lb.  hr.  . 

307 

613 

767 

575 

767 

957 

6S9 

1149 

1379 

150 

Lift,  in.  .  .  . 

0.02 

0.04 

0.05 

0.03 

0.04 

0.05 

0.03 

0.05 

0.06 

CH  

529,900 

1,060,000 

1,325,000 

993,500 

1,325,000 

1,656,000 

1  192,000 

1,987,000 

2,384,000 

Lb.  hr.  . 

362 

723 

904 

677 

904 

1129 

813 

1355 

1625 

175 

Lift,  in  

0.02 

0.04 

0.05 

0.03 

0.04 

0.05 

0.03 

0.05 

'  O.C6 

CH  

610,300 

1,221,000 

1,526,000 

1,144,000 

1,526,000 

1,907,000 

1,373,000 

2,286,000 

2,746,000 

Lb.  hr  

416 

833 

1040 

780 

1040 

1301 

936 

1561 

187L 

200 

Lift,  in.  .  .  . 

0.02 

0.04 

0.05 

0.03 

0.04 

0.05 

0.03 

0.05 

0.06 

CH  

690,700 

1,381,000 

1,727,000 

1,295,000 

1,727,000 

2,158,000 

1,554,000 

2,590,000 

3,108,000 

Lb.  hr.  . 

471 

941 

1178 

883 

1178 

1472 

1060 

1766 

2111 

225 

Lift,  in.  .  .  . 

0.02 

0.04 

0.05 

0.03 

0.04 

0.05 

0.03 

0.05 

0.06 

CH  

771,100 

1,542,000 

1,928,000 

1,446,000 

1,928,000 

2,410:000 

1,735,000 

2,892,000 

3,470,000 

Lb.  hr.  . 

526 

1052 

1315 

98G 

1315 

1643 

1183 

1972 

236f 

250 

Lift,  in  

0.02 

0.04 

0.05 

0.03 

0.04 

0.05 

0.03 

0.05 

0.06 

CH  

851,600 

1,703,000 

2  129,000 

1,597,000 

2,129,OCO 

2,661,000 

1,916,000 

3,193,000 

3,832,000 

Lb.  hr  

581 

1161 

1451 

1089 

1451 

1814 

1307 

2177 

8612 

275 

Lift,  in.  .  .  . 

0.02 

O.C4 

0.05 

0.03 

O.C4 

0.05 

0.03 

0.05 

0.06 

CH 

932,000 

1,864,000 

2,330,000 

1,748,000 

2,330,000 

2,913,000 

2,097,000 

3,495,000 

4,194,00( 

Lb.  hr.  . 

635 

1271 

15S9 

1192 

15S9 

1986 

1430 

2383 

2860 

300 

Lift,  in.  .  .  . 

0.02 

0.04 

0.05 

0.03 

0.04 

0.05 

0.03 

0.05 

0.06 

CH  

1,024,000 

2,048,000 

2,531,000 

1,898,000 

2,531,000 

3,164,000 

2,278,000 

3,797,000 

4,556,000 

Lb.  hr.  .  .  . 

698 

1397 

1746 

1294, 

1726 

2157 

1553 

2589 

3107 

The  Discharge  capacity  of  a  Flat  Seat  Valve  of  a  given  diameter  with  a  given  lift  may  be  obtained  by  multiplying 
the  discharge  capacity  given  in  the  Table  for  a  45  deg.  bevel  seat  valve  of  same  diameter  and  same  lift,  by  1.4. 

70 


TABLE  8  (CONTINUED)      DISCHARGE  CAPACITIES  FOR  DIRECT  SPRING-LOADED  POP 
SAFETY  VALVES,  WITH  45  DEG.  BEVEL  SEATS 


Gage 
Pres., 
T.b.  per 
Si.  In. 

Diameter,  2  In. 

Diameter,  2J^  In. 

Diameter,  3  In. 

Min. 

Int. 

Max. 

Min. 

Int. 

Max. 

Min. 

Int. 

Max. 

15 

Lift,  in  

0.04 

0.06 

0.07 

0.04 

0.06 

0.08 

0.05 

0.08 

0.10 

CH  

382,200 

573,300 

668,900 

477,700 

716,600 

955,500 

716,600 

1,147,000 

1,433,000 

Lb.hr.  . 

261 

391 

456 

326 

488 

651 

489 

782 

977 

2«j 

Lift,  in.  .  .  . 

0.04 

0.06 

0.07 

0.04 

0.06 

0.08 

0.05 

0.08 

0.10 

CH  

510,900 

766,300 

894,000 

638,500 

957,900 

1,277,000 

957,900 

1,533,000 

1,916,000 

T,b.  hr  

349 

523 

610 

435 

653 

871 

653 

1046 

1307 

50 

Lift,  in  

0.04 

0.06 

0.07 

0.04 

0.06 

0.08 

0.05 

0.08 

0.10 

CH  

832,600 

1,249,000 

1,457,000 

1,041,000 

1,561,000 

2,081,000 

1,561,000 

2,498,000 

3,122,000 

Lb.  hr  

5C8 

851 

994 

710 

1064 

1419 

1064 

1703 

212C 

75 

Lift,  in.... 

0.04 

0.06 

0.07 

0.04 

0.06 

0.08 

0.05 

0.08 

0.10 

CH  

1,154,000 

1,731,000 

2,020,000 

1,443,000 

2,164,000 

2,886,000 

2,164,000 

3,463,000 

4,329,000 

Lb.  hr  

787 

1181 

1377 

984 

1475 

1968 

1475 

2361 

2951 

100 

Lift,  in.  .  .  . 

0.04 

0.06 

0.07 

0.04 

0.06 

0.08 

0.05 

0.08 

0.10 

CH  

1,476,000 

2,214,000 

2,583,000 

1,845,000 

2,768,000 

3,690,000 

2,768,000 

4,428,000 

5,535,000 

Lb.  hr.  .  . 

1007 

1510 

1761 

1258 

1887 

251C 

1887 

3019 

3774 

125 

Lift,  in.  .  .  . 

0.04 

0.06 

0.07 

0.04 

0.06 

o.os 

0.05 

0.08 

0.10 

CH  

1,795,000 

2,693,000 

3,146,000 

2,247,000 

3,371,000 

4,494,000 

3,371,000 

5,393,000 

6,741,000 

Lb.  hr  

1224 

1836 

2145 

1532 

2299 

3004 

2299 

3677 

4596 

150 

Lift,  in.... 

0.04 

0.06 

0.07 

0.04 

0.06 

0.08 

0.05 

0.08 

0.10 

CH  

2,109,000 

3,179,000 

3,709,000 

2,649,000 

3,974,000 

5,299,000 

3,974,000 

6,358,000 

7,948,000 

Lb.  hr.  .  .  . 

1438 

2158 

2529 

1806 

2710 

3613 

2710 

4335 

5419 

175 

Lift,  in.  .  .  . 

0.04 

0.06 

0.07 

0.04 

0.06 

0.08 

0.05 

0.08 

0.10 

CH   

2,441,000 

3,662,000 

4,272,000 

3,051,000 

4,577,000 

6,103,000 

4,577,000 

7,323,000 

9,154,000 

Lb.  hr  

1664 

2497 

2913 

2081 

3121 

4161 

3121 

4993 

6242 

200 

Lift,  in  

0.04 

0.06 

0.07 

0.04 

0.06 

0.08 

0.05 

.  0.08 

0.10 

CH  

2,763,000 

4,144,000 

4,835,000 

3,454,000 

5,180,000 

6,907,000 

5,180,000 

8,289,000 

10,361,000 

Lb.  hr  .  . 

1884 

2826 

.  3296 

2354 

3532 

4709 

3532 

5651 

7064 

225 

Lift,  in  .... 

0.04 

0.06 

0.07 

0.04 

0.06 

0.08 

0.05 

0.08 

0.10 

CH 

3,085,000 

4,626,000 

5,398,000 

3,856,000 

5,784,000 

7,711,000 

5,784,000 

9,254,000 

11,567,000 

Lb.  hr.  . 

2104 

3154 

3680 

2629 

3944 

5258 

3944 

6310 

7890 

250 

Lift.  in.... 

0.04 

0.06 

0.07 

0.04 

0.06 

0.08 

0.05 

0.08 

0.10 

CH  

3,406,000 

5,109,000 

5,961,000 

4,258,000 

6,387,000 

8,516,000 

6,387,000 

10,219,000 

12,774,000 

Lb.  hr.  .  .  . 

2322 

3484 

4064 

2903 

4355 

5807 

4355 

6968 

8708 

275 

Lift,  in  

0.04 

0.06 

0.07 

0.04 

0.06 

0.08 

0.05 

0.08 

0.10 

CH  

3,728,000 

5,592,000 

6,524,000 

4,660,000 

6,990,000 

9,320,000 

6,990,000 

11,180,000 

13,980,000 

Lb.  hr  

2542 

3813 

4448 

3177 

4766 

6355 

4766 

7620 

9533 

300 

Lift,  in  

0.04 

0.06 

0.07 

0.04 

0.06 

0.08 

0.05 

0.08 

0.10 

CH  

4,050,000 

6,075,000 

7,087,000 

5,062,000 

7,593,000 

10,124,000 

7,593,000 

12,149,000 

15,186,000 

Lb.  hr.  . 

2762 

4143 

4832 

3452 

5177 

6903 

5177 

8280 

10,358 

The  Discharge  capacity  of  a  Flat  Seat  Valve  of  a  given  diameter  with  a  given  lift  may  be  obtained  by  multiplying 
the  discharge  capacity  given  in  the  Table  for  a  45  deg.  bevel  seat  valve  of  same  diameter  and  same  lift,  by  1.4. 

This  table  is  concluded  on  the  following 
71 


TABLE  8  (CONCLUDED)     DISCHARGE  CAPACITIES  FOR  DIRECT  SPRING-LOADED  POP  SAFETY 
VALVES,  WITH  45  DEG.  BEVEL  SEATS 


Gage 
Pres., 
Lb.  por 

Sq.  In. 

Diameter,  3^  In. 

Diameter,  4  In. 

Diameter,  4H  In. 

Min. 

Int. 

Max. 

Mm. 

Int. 

Max. 

Min. 

Int. 

Max. 

Lift,  in  

0.06 

0.09 

0.11 

0.07 

0.10 

0.12 

0.08 

0.11 

0.13 

15 

CH  

1,003,000 

1,505,000 

1,839,000 

1,338,000 

1,911,000 

2,293,000 

1,720,000 

2,365,000 

2,795,000 

Lb.  hr.  . 

684 

1026 

1254 

912 

1303 

1564 

1173 

1613 

1906 

Lift,  in  .... 

0.06 

0.09 

0.11 

0.07 

0.10 

0.12 

0.08 

0.11 

0.13 

25 

CH  

1,341,000 

2,012,000 

2,459,000 

1,788,000 

2,554,000 

3,065,000 

2,299,000 

3,161,000 

3,736,000 

Lb.  hr  

914 

1372 

1676 

1219 

1742 

2090 

1568 

2156 

2547 

50 

Lift,  in.... 

0.06 

0.09 

0.11 

0.07 

0.10 

0.12 

0.08 

0.11 

0.13 

CH  

2,186,000 

3,278,000 

4,007,000 

2,914,000 

4,163,000 

4,996,000 

3,747,000 

5,152,000 

6,088,000 

Lb.  hr.  .  . 

1490 

2235 

2732 

1987 

2839 

3406 

2555 

3513 

4151 

Lift,  in.  .  .  . 

0.06 

0.09 

0.11 

0.07 

0.10 

0.12 

0.08 

0.11 

0.13 

75 

CH  

3,030,000 

4,545,000 

5,555,000 

4,040,000 

5,772,000 

6,926,000 

5,194,000 

7,142,000 

8,441,000 

Lb.  hr  

2066 

3099 

3788 

2754 

3935 

4722 

3542 

4870 

5756 

jift,  in.  .  .  . 

0.06 

0.09 

0.11 

0.07 

0.10 

0.12 

0.08 

0.11 

0.13 

100 

CH  

3,875,000 

5,812,000 

7,103,000 

5,166,000 

7,380,000 

8  856,000 

6  642  000 

9,133,000 

10,793,000 

Lb.  hr  

2642 

39G3 

4843 

3522 

5032 

6038 

4529 

6227 

7358 

Lift,  in.... 

0.06 

0.09 

0.11 

0.07 

0.10 

0.12 

0.08 

0.11 

0.13 

125 

CH.  . 

4,719,000 

7,079,000 

8,652,000 

6,292,000 

8,988,000 

10,786,000 

8,089,000 

11,123,000 

13,146,000 

Lb.  hr.  . 

3218 

4826 

5899 

4290 

6128 

7354 

5516 

7583 

8963 

l<if  t,  in  .... 

0.06 

0.09 

0.11 

0.07 

0.10 

0.12 

0.08 

0.11 

0.13 

150 

CH  

5,564,000 

8,345,000 

10,199,000 

7,418,000 

10,597,000 

12,717,000 

9,537,000 

13,114,000 

15,498,000 

Lb.  hr  

3794 

5G90 

6954 

5058 

7226 

8670 

6503 

8940 

10566 

175 

Lift,  in  .... 

0.06 

0.09 

0.11 

0.07 

0.10 

0.12 

0.08 

0.11 

0.13 

CH  

6,408,000 

9,612,000 

11,748,000 

8,544,000 

12,206,000 

14,647,000 

10,985,000 

15,105,000 

17,851,000 

Lb.  hr  

4369 

6553 

8010 

5824 

8320 

9984 

7490 

10298 

12173 

200 

Lift,  in  .... 

0.06 

0.09 

0.11 

0.07 

0.10 

0.12 

0.08 

0.11 

0.13 

CH........ 

7,253,000 

10,879,000 

13,296,000 

9,670,000 

13,814,000 

16,580,000 

12,433,000 

17,095,000 

20,204,000 

Lb.  hr.  . 

•4946 

7418 

90G8 

6593 

9420 

11305 

8475 

11655 

13773 

225 

Lift,  in.... 

0.06 

0.09 

0.11 

0.07 

0.10 

0.12 

0.08 

0.11 

0.13 

CH     . 

8,097,000 

12,146,000 

14,845,000 

10,796,000 

15,423,000 

18,507,000 

13,881,000 

19,086,000 

22,556,000 

Lb.  hr  

5521 

8280 

10120 

7361 

10514 

12616 

9465 

13013 

15383 

250 

Lift,  in  

0.06 

0.09 

0.11 

0.07 

0.10 

0.12 

0.08 

0.11 

0.13 

CH  

8,942,000 

13,412,000 

16,393,000 

11,922,000 

17,031,000 

20,438,000 

15,328,000 

21,076,000 

24,908,000 

Lb.  hr.  . 

6097 

9143 

11175 

8130 

11614 

13938 

10448 

14366 

16980 

275 

Lift,  in  

0.06 

0.09 

0.11 

0.07 

0.10 

0.12 

0.08 

0.11 

0.13 

CH  

9,786,000 

14,679,000 

17,941,000 

13,048,000 

18,640,000 

22,368,000 

16,776,000 

23,067,000 

27,261,000 

Lb.  hr.  . 

6672 

10005 

12233 

8S95 

12707 

15248 

11438 

15728 

18585 

300 

Lift,  in.  . 

0.06 

0.09 

0.11 

0.07 

0.10 

0.12 

0.08 

0.11 

0.13 

CH  

10,630,000 

15,946,000 

19,489,000 

14,174,000 

20,249,000 

24,298,000 

18,224,000 

25,058,000 

29,614,000 

Lb.  hr  

7248 

10875 

13290 

96f8 

13807 

16568 

12428 

17088 

20195 

The  Discharge  capacity  of  a  Flat  Seat  Valve  of  a  given  diameter  with  a  given  lift  may  be  obtained  by  multiplying 
the  discharge  capacity  given  in  the  Table  for  a  45  deg.  bevel  seat  valve  of  same  diameter  and  same  lift,  by  1.4. 

72 


NEW  INSTALLATIONS,  PART  I,  SECTION   I,  POWER  BOILERS  73 

2-75  .Safety  valve  capacity  may  be  checked  in  any  one  of  three 
different  ways,  and  if  found  sufficient,  additional  capacity  need  not  be 
provided :  • 

a  By  making  an  accumulation  test,  by  shutting  off  all  other 
steam  discharge  outlets  from  the  boiler  and  forcing  the 
fires  to  the  maximum.  The  safety  valve  equipment  shall 
be  sufficient  to  prevent  an  excess  pressure  beyond  six  per 
cent  as  specified  in  Par.  270. 

b  By  measuring  the  maximum  amount  of  fuel  that  can  be 
burned  and  computing  the  corresponding  evaporative  ca- 
pacity upon  the  basis  of  the  heating  value  of  the  fuel.  See 
Appendix,  Pars.  421  to  427. 

c  By  determining  the  maximum  evaporative  capacity  by 
measuring  the  feed  water.  The  sum  of  the  safety  valve 
capacities  marked  on  the  valves,  shall  be  equal  to  or  greater 
than  the  maximum  evaporative  capacity  of  the  boiler. 

276  When  two  or  more  safety  valves  are  used  on  a  boiler,  they 
may  be  either  separate  or  twin  valves  made  by  mounting  individual 
valves  on  Y-bases,  or  duplex,  triplex  or  multiplex  valves  having  two 
or  more  valves  in  the  same  body  casing. 

277  The  safety  valve  or  valves  shall  be  connected  to  the  boiler 
independent  of  any  other  steam  connection,  and  attached  as  close  as 
possible  to  the  boiler,  without  any  unnecessary  intervening  pipe  or 
fitting.    Every  safety  valve  shall  be  connected  so  as  to  stand  in  an  up- 
right position,  with  spindle  vertical,  when  possible. 

278  Each  safety  valve  shall  have  full  sized  direct  connection  to 
the  boiler.     No  valve  of  any  description  shall  be  placed  between  the 
safety  valve  and  the  boiler,  nor  on  the  discharge  pipe  between  the 
safety  valve  and  the  atmosphere.    When  a  discharge  pipe  is  used,  it 
shall  be  not  less  than  the  full  size  of  the  valve,  and  shall  be  fitted 
with  an  open  drain  to  prevent  water  from  lodging  in  the  upper  part  of 
the  safety  valve  or  in  the  pipe. 

279  If  a  muffler  is  used  on  a  safety  valve  it  shall  have  sufficient 
outlet  area  to  prevent  back  pressure  from  interfering  with  the  proper 
operation  and  discharge  capacity  of  the  valve.     The  muffler  plates  or 
other  devices  shall  be  so  constructed  as  to  avoid  any  possibility  of  re- 
striction of  the  steam  passages  due  to  deposit.     When  an  elbow  is 
placed  on  a  safety  valve  discharge  pipe,  it  shall  be  located  close  to  the 
safety  valve  outlet  or  the  pipe  shall  be  securely  anchored  and  supported. 
All  safety  valve  discharges  shall  be  so  located  or  piped  as  to  be  carried 


74  REPORT  OF  BOILER  CODE  COMMITTEE,  AM.SOC.M.E. 

clear  from  running  boards  or  working  platforms  used  in  controlling  the 
main  stop  valves  of  boilers  or  steam  headers. 

280  When  a  boiler  is  fitted  with  two  or  more  safety  valves  on  one 
connection,  this  connection  to  the  boiler  shall  have  a  cross-sectional 
area  not  less  than  the  combined  area  of  all  of  the  safety  valves  with 
which  it  connects. 

281  .Safety  valves  shall  operate  without  chattering  and  shall  be 
set  and  adjusted  as  follows :    To  close  after  blowing  down  not  more 
than  4  Ib.  on  boilers  carrying  an  allowed  pressure  less  than  100  Ib. 
per  sq.  in.  gage.     To  close  after  blowing  down  not  more  than  G  Ib.  on 
boilers  carrying  pressures  between  100  and  200  Ib.  per  sq.  in.  gage 
inclusive.    To  close  after  blowing  down  not  more  than  8  Ib.  on  boilers 
carrying  over  200  Ib.  per  sq.  in.  gage. 

282  Each  safety  valve  used  on  a  boiler  shall  have  a  substantial 
lifting  device,  and  shall  have  the  spindle  so  attached  that  the  valve 
disc'  can  be  lifted  from  its  seat  a  distance  not  less  than  one-tenth  of 
the  nominal  diameter  of  the  valve,  when  there  is  no  pressure  on  the 
boiler. 

283  The  seats  and  discs  of  safety  valves  shall  be  of  non-ferrous 
material. 

.284  Springs  used  in  safety  valves  shall  not  show  a  permanent  set 
exceeding  1/32  in.  ten  minutes  after  being  released  from  a  cold  com- 
pression test  closing  the  spring  solid. 

285  The  spring  in   a   safety  valve   shall  not  be  used  for   any 
pressure  more  than  10  per  cent  above  or  below  that  for  which  it  was 
designed. 

286  A  safety  valve  over  3-in.  size,  used  for  pressures  greater  than 
15  Ib.  per  sq.  in.  gage,  shall  have  a  flanged  inlet  connection.     The 
dimensions  of  the  flanges  shall  conform  to  the  American  standard 
given  in  Tables  15  and  16  of  the  Appendix. 

287  When    the  letters  A  8  M  E  Std  are  plainly  stamped  or  cast 
on  the  valve  body  this  shall  be  a  guarantee  by  the  manufacturer  that 
trie  valve  conforms  with  the  details  of  construction  herein  specified. 

,288  Every  superheater  shall  have  one  or  more  safety  valves  near 
the  outlet.  The  discharge  capacity  of  the  safety  valve  or  valves  on 
an  attached  superheater  may  be  included  in  determining  the  number 
and  sizes  of  the  safety  valves  for  the  boiler,  provided  there  are  no  in- 
tervening valves  between  the  superheater  safety  valve  and  the  boiler. 

£89  Every  safety  valve  used  on  a  superheater,  discharging  super- 
heated steam,  shall  have  a  steerbody  with  a  flanged  inlet  connection, 


NEW  INSTALLATIONS,  PART  I,  SECTION  I,  POWER  BOILERS  75 

and  shall  have  the  scat  and  disc  of  nickel  composition  or  equivalent 
material,  and  the  spring  fully  exposed  outside  of  the  valve  casing  so 
that  it  shall  he  protected  from  contact  with  the  escaping  steam. 

290  Every  hoiler  shall  have  proper  outlet  connections  for  the 
required  safety  valve  or  valves,  independent  of  any  other  steam  outlet 
connection  or  of  any  internal  pipe  in  the  steam  space  of  the  hoiler,  the 
area  of  opening  to  he  at  least  equal  to  the  aggregate  area  of  all  of  the 
safety  valves  to  he  attached  thereto. 

WATER  AND  STEAM  GAGES 

291  Water  Glasses  and  Gage  Cocks.     Each  boiler  shall  have  at 
least  one  water  glass,  the  lowest  visible  part  of  which  shall  be  not  less 
than  2  in.  above  the  lowest  permissible  water  level. 

292  No  water  glass  connection  shall  be  fitted  with  an  automatic 
shut-off  valve. 

,293  When  shut-off s  are  used  on  the  connections  to  a  water 
column,  they  shall  be  either  outside  screw  and  yoke  type  gate  valves 
or  stop  cocks  with  levers  permanently  fastened  thereto,  and  such 
valves  or  cocks  shall  be  locked  or  sealed  open. 

294  Each  boiler  shall  have  three  or  more  gage  cocks,  located 
within  the  range  of  the  visible  length  of  the  water  glass,  except  when 
such  boiler  has  two  water  glasses  with  independent  connections  to  the 
boiler  and  located  on  the  same  horizontal  line  and  not  less  than  2  ft. 
apart. 

295  ~Ko  outlet  connections,  except  for  clamper  regulator,  feed- 
water  regulator,  drains  or  steam  gages,  shall  be  placed  on  the  pipes 
connecting  a  water  column  to  a  boiler. 

296  Steam  Gages.     Each  boiler  shall  have  a  steam  gage  con- 
nected to  the  steam  space  or  to  the  water  column  or  its  steam  connec- 
tion.    The  steam  gage  shall  be  connected  to  a  syphon  or  equivalent 
device  of  sufficient  capacity  to  keep  the  gage  tube  filled  with  water 
and  so  arranged  that  the  gage  cannot  be  shut  off  from  the  boiler 
except  by  a  cock  placed  near  the  gage  and  provided  with  a  tee  or  lever 
handle  arranged  to  be  parallel  to  the  pipe  in  which  it  is  located  when 
the  cock  is  open.     Connections  to  gages  shall  be  of  brass,  copper  or 
bronze  composition. 

297  The  dial  of  the  steam  gage  shall  be  graduated  to  not  less 
than  iy2  times  the  maximum  allowable  working  pressure  on  the  boiler. 

298  Each  boiler  shall  be  provided  with  a  ^-in.  pipe  size  valved 


76  REPORT  OF  BOILER  CODE  COMMITTEE,  AM.SOC.M.E. 

connection  for  attach  ing  a  test  gage  when  the  hoiler  is  in  service,  so 
that  the  accuracy  of  the  boiler  steam  gage  can  be  ascertained. 

FITTINGS  AND  APPLIANCES 

299  Nozzles  and  Fittings.     All   fittings  shall   conform  to   the 
American   Standards  given   in   Tables   15   or   16   of  the   Appendix. 
Where  the  maximum  allowable  working  pressure  is  less  than  125  Ib. 
per  sq.  in.,  Table  15  shall  be  used  and  where  higher,  Table  16. 

300  The  minimum  number  of  threads  that  a  pipe  or  fitting  shall 
screw  into  a  tapped  hole  shall  correspond  to  the  numerical  values 
given  for  number  of  threads  in  Table  7. 

301  Stop  Valves.     Each  steam  discharge  outlet  over  2  in.  in  di- 
ameter, except  safety  valve  and  superheater  connections,  shall  be  fitted 
with  a  stop  valve  or  valves  of  the  outside  screw  and  yoke  type,  located 
as  near  the  boiler  as  practicable. 

302  The  main  stop  valves  of  boilers  shall  be  extra  heavy  when 
the  maximum  allowable  working  pressure  exceeds  125  Ib.  per  sq.  in. 
The  fittings  between  the  boiler  and  such  valve  or  valves  shall  be  extra 
heavy,  as  specified  in  Table  16  of  the  Appendix. 

303  When  two  or  more  boilers  are  connected  to  a  common  steam 
main,  two  stop  valves,  with  an  ample  free  blow  drain  between  them., 
shall  be  placed  in  the  steam  connection  between  each  boiler  and  the 
steam  main.    The  discharge  of  this  drain  valve  must  be  visible  to  the 
operator  while  manipulating  the  valve.     The  stop  valves  shall  consist 
preferably  of  one  automatic  non-return  valve   (set  next  the  boiler) 
and  a  second  valve  of  the  outside  screw  and  yoke  type ;  or,  two  vaives 
of  the  outside  screw  and  yoke  type  may  be  used. 

30-t    When  a  stop  valve  is  so  located  that  water  can  accumulate, 
ample  drains  shall  be  provided. 

305  Steam  Mains.     Provisions  shall  be  made  for  the  expansion 
and  contraction  of  steam  mains  connected  to  boilers,  by  providing 
substantial  anchorage  at  suitable  points,  so  that  there  shall  be  no 
undue  strain  transmitted  to  the  boiler.    -Steam  reservoirs  shall  be  used 
on  steam  mains  when  heavy  pulsations  of  the  steam  currents  cause 
vibration  of  the  boiler  shell  plates. 

306  Each  superheater  shall  be  fitted  with  a  drain. 

307  Blow-off  Piping.     The  size  of  a  surface  blow-off  pipe  shall 
not  exceed  1%  in.,  and  it  shall  be  carried  through  the  shell  or  head 
with  a  brass  or  steel  boiler  bushing. 


NEW  INSTALLATIONS,  PART  I,  SECTION   I,  POWER  BOILERS  77 

308  Each  boiler  shall  have  a  bottom  blow-off  pipe,  fitted  with  a 
valve  or  cock,  in  direct  connection  with  the  lowest  water  space  prac- 
ticable ;  the  minimum  size  of  pipe  and  fittings  shall  be  1  in.  and  the 
maximum  size  shall  be  2l/2  in.     Globe  valves  shall  not  be  used  on 
such  connections. 

309  A  bottom  blow-off  cock  shall  have  the  plug  held  in  place  by 
a  guard  or  gland.     The  end  of  the  plug  shall  be  distinctly  marked  in 
line  with  the  passage. 

310  The  blow-off  pipe  or  pipes  shall  be  extra  heavy  from  boiler 
to  valve  or  valves,  and  shall  run  full  size  without  reducers  or  bushings. 
All  fittings  between  the  boiler  and  valves  shall  be  of  steel. 

311  When  the  maximum  allowable  working  pressure  exceeds  12<5 
Ib.  per  sq.  in.,  the  bottom  blow-off  pipe  shall  have  two  valves,  or  a  valve 
and  a  cock,  and  such  valves,  or  valve  and  cock,  shall  be  extra  heavy, 
except  that  on  a  boiler  having  multiple  blow-off  pipes,  a  single  master 
valve  may  be  placed  on  the  common  blow-off  pipe  from  the  boiler,  in 
which  case  only  one  valve  on  each  individual  blow-off  is  required. 

312  A  bottom  blow-off  pipe  when  exposed  to  direct  furnace  heat 
shall  be  protected  by  fire-brick,   a  substantial   cast-iron  removable 
sleeve  or  a  covering  of  non-conducting  material. 

313  An  opening  in  the  boiler  setting  for  a  blow-off  pipe  shall  be 
arranged  to  provide  for  free  expansion  and  contraction. 

314  Feed  Piping.     The  feed  pipe  of  a  boiler  shall  have  an  open 
end  or  ends.    Wherever  globe  valves  are  used  on  feed  piping,  the  inlet 
.shall  be  under  the  disc  of  the  valve. 

315  The  feedwater  shall  discharge  at  about  three-fifths  the  length 
of  a    horizontal  return  tubular  boiler  from  the  front  head  (except  a 
horizontal  return  tubular  boiler  equipped  with  an  auxiliary  feedwater 
heating  and  circulating  device),  above  the  central  rows  of  tubes,  when 
the  diameter  of  the  boiler  exceeds  36  in.    The  feed  pipe  shall  be  car- 
ried through  the  head  or  shell  near  the  front  end  with  a  brass  or  steel 
boiler  bushing,  and  securely  fastened  inside  the  shell  above  the  tubes. 

316  Feedwater  shall  not  discharge  in  a  boiler  close  to  riveted 
joints  in  the  shell  or  to  furnace  sheets. 

317  The  feed  pipe  shall  be  provided  with  a  check  valve  near 
the  boiler  and  a  valve  or  cock  between  the  check  valve  and  the  boiler, 
and  when  two  or  more  boilers  are  fed  from  a  common  source,  there 
shall  also  be  a  globe  valve  on  the  branch  to  each  boiler,  between  the 
check  valve  and  the  source  of  supply. 


73  REPORT  OF  BOILER  CODE  COMMITTEE,  AM.SOC.M.E. 

318  When  a  pump,  inspirator  or  injector  is  required  to  supply 
feedwater  to  a  boiler  plant  of  over  50  h.  p.,  more  than  one  such 
appliance  shall  be  provided. 

319  Lamplirey  Fronts.     Each   boiler   fitted   with   a   Lamphrey 
boiler  furnace  mouth  protector,  or  similar  appliance,  having  valves 
on  the  pipes  connecting  them  to  the  boiler,  shall  have  these  valves 
locked  or  sealed  open.    Such  valves  when  used,  shall  be  of  the  straight- 
way type. 

320  Water  Column  Pipes.     The  minimum  size  of  pipes  connect- 
ing the  water  column  to  a  boiler  shall  be  1  in.     Water-glass  fittings 
or  gage  cocks  may  be  connected  direct  to  the  boiler. 

3.21  The  water  connections  to  the  water  column  of  a  boiler  shall 
be  of  brass  and  shall  be  provided  with  a  cross  to  facilitate  cleaning. 
Either  the  water  column  or  this  connection  shall  be  fitted  with  a 
drain  cock  or  drain  valve  with  a  suitable  connection  to  the  ashpit,  or 
other  safe  point  of  waste.  The  water  column  blow-off  pipe  shall  be 
at  least  %  in- 

3i2>2  The  steam  connection  to  the  water  column  of  a  horizontal 
return  tubular  boiler  shall  be  taken  from  the  top  of  the  shell  or  the 
upper  part  of  the  head  ;  the  water  connection  shall  be  taken  from  a 
point  not  less  than  6  in.  below  the  center  line  of  the  shell. 

SETTING 

3(23  Methods  of  Support.  A  horizontal  return  tubular  boiler 
over  78-in.  in  diameter  shall  be  supported  from  steel  lugs  by  the  out- 
side suspension  type  of  setting,  independent  of  the  boiler  side  walls. 
The  lugs  shall  be  so  designed  that  the  load  is  properly  distributed 
between  the  rivets  attaching  them  to  the  shell  and  so  that  not  more 
than  two  of  these  rivets  come  in  the  same  longitudinal  line  on  each 
lug.  The  distance  girthwise  of  the  boiler  from  the  centers  of  the 
bottom  rivets  to  the  centers  of  the  top  rivets  attaching  the  lugs  shall 
be  not  less  than  12  in.  The  other  rivets  used  shall  be  spaced  evenly 
between  these  points.  If  more  than  four  lugs  are  used  they  shall  be 
set  in  four  pairs. 

3i24  A  horizontal  return  tubular  boiler  over  54  in.,  and  up  to 
and  including  78  in.  in  diameter,  shall  be  supported  by  the  outside 
suspension  type  of  setting,  or  at  four  points  by  not  less  than  eight 
steel  or  cast-iron  brackets  set  in  pairs.  A  horizontal  return  tubular 
boiler  up  to  and  including  54  in.  in  diameter  shall  be  supported  by 
the  outside  suspension  type  of  setting,  or  by  not  less  than  two  steel 
or  cast-iron  brackets  on  each  side. 


NEW  INSTALLATIONS,  PART  I,  SECTION  I,  TOWER  BOILERS  79 

3,2>5  Lugs  or  brackets,  when  used  to  support  boilers,  shall  be 
properly  fitted  to  the  surfaces  to  which  they  are  attached.  The 
shearing  stress  on  the  rivets  used  for  attaching  the  lugs  or  brackets 
shall  not  exceed  8  per  cent  of  the  strength  given  in  Par.  16. 

326  Wet-bottom  stationary  boilers  shall  have  a  space  of  not  less 
than  12  in.  between  the  bottom  of  the  boiler  and  the  floor  line,  with 
access  for  inspection. 

3,27  Access  and  Firing  Doors.  The  minimum  size  of  an  access 
door  to  be  placed  in  a  boiler  setting  shall  be  12  X  16  in.  or  equivalent 
area,  11  in.  to  be  the  least  dimension  in  any  case. 

328  A  water  tube  boiler  which  is  fired  by  hand  shall  have  firing 
door  or  doors  of  the  inward  opening  type  unless  such  doors  are  pro- 
vided with  substantial  latching  devices  to  prevent  them  from  being 
blown  open  by  pressure  on  the  furnace  side. 

HYDROSTATIC  TESTS 

32-9  Hydrostatic  Pressure  Tests.  After  a  boiler  has  been  com- 
pleted, it  shall  be  subjected  to  a  hydrostatic  test  of  one  and  one-half 
times  the  maximum  allowable  working  pressure.  The  pressure  shall 
be  under  proper  control  so  that  in  no  case  shall -the  required  test 
pressure  be  exceeded  by  more  than  6  per  cent. 

330  During  a  hydrostatic  test,  the  safety  valve  or  valves  shall 
be  removed  or  each  valve  disc  shall  be  held  to  its  seat  by  means  of  a 
testing  clamp  and  not  by  screwing  down  the  compression  screw  upon 
the  spring. 

STAMPING 

331  Stamping  of  Boilers.     In.  laying  out  shell  plates,  furnace 
sheets  and  heads  in  the  boiler  shop,  care  shall  be  taken  to  leave  at 
least  one  of  the  stamps,  specified  in  Par.  36  of  these  Rules,  so  located 
as  to  be  plainly  visible  when  the  boiler  is  completed;  except  that  the 
tube  sheets  of  a  vertical  fire-tube  boiler  and  butt  straps  shall  have  at 
least  a  portion  of  such  stamps  visible  sufficient  for  identification  when 
the  boiler  is  completed. 

33.2  Each  boiler  shall  conform  in  every  detail  to  these  Rules,  and 
shall  be  distinctly  stamped  with  the  symbol  as  shown  in  Fig.  19,  de- 
noting that  the  boiler  was  constructed  in  accordance  therewith.  Each 
boiler  shall  also  be  stamped  by  the  builder  with  a  serial  number  and 


80  REPORT  OF   BOILER  CODE  COMMITTEE,  AM.SOC.M.E. 

with  the  builder's  name  cither  in  full  or  abbreviated,  as  indicated  in 
Fig.  20.  The  height  of  the  letters  and  figures  used  in  stamping  shall 
be  not  less  than  y±  in.  and  this  stamp  shall  be  placed  directly  below 
or  alongside  The  American  Society  of  Mechanical  Engineers'  stamp. 


(Name  of  State) 

STD 

(Number  of  Boiler)  f 
(Name  of  Builder) 


FIG.  19     OFFICIAL  SYMBOL  FOR  STAMP         FIG.  20     FORM  OF  STAMP  PROPOSED 
TO   DENOTE   THE  AMERICAN   So-  FOR  THE  BOILER  MANUFACTURER 

CIETY  OF  MECHANICAL  ENGI- 
NEERS UNIFORM  STANDARD 

33i3  Location  of  Stamps.  The  location  of  stamps  shall  be  as 
follows : 

a  On  horizontal  return  tubular  boilers — on  the  front  head, 
above  the  central  rows  of  tubes. 

b  On  horizontal  flue  boilers — on  the  front  head,  above  the 
flues. 

c  On  traction,  portable  or  stationary  boilers  of  the  locomo- 
tive type  or  ,Star  water- tube  boilers — on  the  furnace  end, 
above  the  handhole. 

d  On  vertical  fire  tube  and  vertical  submerged  tube  boilers — 
on  the  shell  above  the  fire  door. 

6  On  water-tube  boilers,  Babcock  &  Wilcox,  /Stirling,  Heine 
and  Eobb-Mumford  standard  types — on  a  head  above 
the  manhole  opening,  preferably  on  the  flanging  of  the 
manhole  opening. 

/  On  vertical  boilers,  Climax  or  Hazleton  type — on  the  top 
head. 

g  On  Cahall  or  Wickes  vertical  water  tube  boilers — on  the 
upper  drum,  above  the  manhole  opening. 

Ji  On  Scotch  marine  boilers — on  the  front  head,  above  the 
center  or  right-nand  furnace. 

i  On  Economic  boilers — on  the  front  head,  above  the  central 
row  of  tubes. 

j  For  other  types  and  new  designs — in  a  conspicuous  loca- 
tion. 

334  The  American  Society  of  Mechanical  Engineers'  standard 
stamp  and  the  boiler  builder's  stamps  shall  not  be  covered  by  insulat- 
ing or  other  material. 


PART  1— SECTION  II 

BOILERS  USED  EXCLUSIVELY  FOR  LOW  PRESSURE 

STEAM  AND  HOT  WATER  HEATING  AND  HOT 

WATER  SUPPLY 

(THIS  DOES  NOT  APPLY  TO  ECONOMIZERS  OB  FEED  WATER  HEATERS.) 

BOILER  MATERIALS 

i 

335  The  Rules  for  power  boilers  shall  apply : 

a  To  all  steel  plate  liot-water  boilers  over  60  in.  in  diameter. 

I  To  all  steel  plate  hot-water  boilers  where  the  grate  area  ex- 
ceeds 10  sq.  ft.  and  the  maximum  allowable  working  pres- 
sure exceeds  50  Ib.  per  sq.  in. 

c  Under  other  conditions,  the  following  rules  shall  apply. 

336  Specifications  are  given  in  these  Rules,  Pars.  23  to  178,  for 
the  important  materials  used  in  the  construction  of  boilers,  and  where 
given,  the  materials  shall  conform  thereto. 

337  Flange  steel  may  be  used  entirely  for  the  construction  of 
steam  heating  boilers  covered  in  this  section,  but  in  no  case  shall 
steel  of  less  than  V4  in.  in  thickness,  nor  tube  sheets  or  heads  of  less 
than  5/16  in.  in  thickness  be  used. 

MAXIMUM  ALLOWABLE  WORKING  PRESSURE 

338  The  maximum  allowable  working  pressure  shall  not  exceed 
15  Ib.  per  sq.  in.  on  a  boiler  built  under  these  Rules  to  be  used  ex- 
clusively for  low  pressure  steam  heating. 

339  A  boiler  to  be  used  exclusively  for  low-pressure  steam  heat- 
ing, may  be  constructed  of  cast-iron,  or  of  cast-iron  excepting  con- 
necting nipples  and  bolts,  or  wholly  of  steel  or  wrought-iron,  or  of 
steel  and  partially  cast-iron,  or  of  steel  or  wrought-iron  with  cast-iron 
mud  rings,  door  frames  and  manhole  flanges. 

340  All  steel  plate,  hot-water  and  steam-heating  boilers  shall  have 
a  factor  of  safety  of  not  less  than  5. 

81. 


82  REPORT  OF  BOILER  CODE  COMMITTEE,  AM.SOC.M.E. 

BOILER  JOINTS 

341  Longitudinal  lap  joints  will  be  allowed  on  boilers  to  be 
used  exclusively  for  low  pressure  steam  heating,  when  the  maximum 
allowable  working  pressure  does  not  exceed  15  Ib.  per  sq.  in.,  and  the 
diameter  of  the  boiler  shell  does  not  exceed  60  in. 

342  The  longitudinal  joints  of  a  horizontal  return  tubular  boiler 
if  of  the  lap  type,  shall  be  not  over  1 2  ft.  in  length. 

343  Iii  a  liot-water  boiler  to  be  used  excusively  for  heating  build- 
ings or  hot  water  supply  when  the  diameter  does  not  exceed  60  in.  and 
the  grate  area  does  not  exceed  10  sq.  ft.,  longitudinal  lap  joints  will 
be  allowed. 

When  the  grate  area  exceeds  10  sq.  ft.  and  the  diameter  of  the 
boiler  does  not  exceed  60  in.  longitudinal  lap  joints  will  be  allowed 
providing  the  maximum  allowable  working  pressure  does  not  exceed 
50  Ib.  per  sq.  in. 

344  Protection   of  Joints.     When  a  boiler   is  built  wholly   or 
partially  of  steel  and  is  used  exclusively  for  low  pressure  steam  heat- 
ing, or  when  a  liot-water  boiler  is  used  exclusively  for  heating  build- 
ings or  for  hot-water  supply,  it  shall  not  be  necessary  to  water  jacket 
the  rivets  in  the  fire-box  where  one  end  of  each  rivet  is  exposed  to  the 
fire  or  direct  radiant  heat  from  the  fire,  provided  any  one  of  the 
following  conditions  is  fulfilled  : 

a  Where  the  ends  of  the  rivets  away  from  the  fire  are  pro- 
tected by  means  of  natural  drafts  of  cold  air  induced  in 
the  regular  operation  of  the  boiler  ; 

b  Where  the  ends  of  the  rivets  away  from  the  fire  are  in  the 
open  air ; 

c  Where  the  rivets  are  protected  by  the  usual  charges  of  fresh 
fuel,  which  is  not  burned  in  contact  with  the  rivets. 

WASHOUT  HOLES 

345  A  boiler  used  for  hot-water  supply  shall  be  provided  with 
washout  holes  for  the  removal  of  any  sediment  that  may  accumulate 
therein. 

BOILER  OPENINGS 

346  Flanged  Connections.     Openings  in  boilers  having  flanged 
connections  shall  have  the  flanges  conform  to  the  American  Standard 


NEW  INSTALLATIONS,   PART  I,   SECTION  II,   HEATING   BOILERS        83 

given  in  Tables  15  or  16  of  the  Appendix,  for  the  corresponding  pipe 
size,  and  shall  have  the  corresponding  drilling  for  bolts  or  studs. 

SAFETY  VALVES 

347  Outlet   Connections  for  .Safety  and  Water  Relief   Valves. 
Every  boiler  shall  have  proper  outlet  connections  for  the  required 
safety,  or  water  relief  valve  or  valves,  independent  of  any  other  con- 
nection outside  of  the  boiler  or  any  internal  pipe  in  the  boiler,  the 
area  of  the  opening  to  be  at  least  equal  to  the  aggregate  area  of  all  of 
the  safety  valves  with  which  it  connects.     A  screwed  connection  may 
be  used  for  attaching  a  safety  valve  to  a  heating  boiler.     This  rule 
applies  to  all  sizes  of  safety  valves. 

348  Safety  Valves.     Each  steam  boiler  shall  be  provided  with 
one  or  more  safety  valves  of  the  spring-pop  type  which  cannot  be 
adjusted  to  a  higher  pressure  than  15  Ib.  per  sq.  in. 

349  Water  Relief  Valves.     Each  hot-water  boiler  shall  be  pro- 
vided with  one  or  more  water  relief  valves  with  open  discharges  hav- 
ing outlets  in  plain  sight. 

350  A  hot-ivater  boiler  built  for  a  maximum  allowable  working: 

o 

pressure  of  30  Ib.  per  sq.  in.  and  used  exclusively  for  heating  build- 
ings, or  for  hot-water  supply,  shall  be  provided  with  a  water  relief 
valve  or  valves,  which  cannot  be  adjusted  for  a  pressure  in  excess 
of  30  Ib.  per  sq.  in. 

351  No  safety  or  water  relief  valve  shall  be  smaller  than  1  in. 
nor  greater  than  4i/>  in.  nominal  size. 

352'    When  two  or  more  safety  or  water  relief  valves  are  used 
on  a  boiler  they  may  be  single  or  twin  valves. 

353  Safety  or  water  relief  valves  shall  be  connected  to  boilers 
independent  of   other   connections   and   be   attached   directly   or   as 
close  as  possible  to  the  boiler,  without  any  intervening  pipe'  or  fittings, 
except  the  Y-base  forming  a  part  of  the  twin  valve  or  the  shortest 
possible  connection.     A  safety  or  water  relief  valve  shall  not  be  con- 
nected to  an  internal  pipe  in  the  boiler.    .Safety  valves  shall  be  con- 
nected so  as  to  stand  upright,  with  the  spindle  vertical,  when  possible. 

354  No  shut-off  of  any  description  shall  be  placed  between  the 
safety  or  water  relief  valves  and  boilers,  nor  on  discharge  pipes  be- 
tween them  and  the  atmosphere. 

355  When  a  discharge  pipe  is  used  its  area  shall  be  not  less  than 
the  area  of  the  valve  or  aggregate  area  of  the  valves  with  which  it 


84  REPORT  OF  BOILER  CODE  COMMITTEE,  AM.SOC.M.E. 

connects,  and  the  discharge  pipe  shall  be  fitted  with  an  open  drain 
to  prevent  water  from  lodging  in  the  upper  part  of  the  valve  or  in 
the  pipe.  When  an  elbow  is  placed  on  a  safety  or  water  relief  valve 
discharge  pipe,  it  shall  be  located  close  to  the  valve  outlet  or  the  pipe 
shall  be  securely  anchored  and  supported.  The  safety  or  water  relief 
valves  shall  be  so  located  and  piped  that  there  will  be  no  danger  of 
scalding  attendants. 

356  Each  safety  valve  used  on  a  steam  heating  boiler  shall  have 
a  substantial  lifting  device  which  shall  be  so  connected  to  the  disc 
that  the  latter  can  be  lifted  from  its  seat  a  distance  of  not  less  than 


TABLE  9     ALLOWABLE  SIZES  OF  SAFETY  VALVES  FOR  HEATING  BOILERS 


Water  Evaporated 

per  Sq.  Ft.  of 

Grate  Surface  per 

75 

100 

160 

160 

200 

240 

Hr.,  Lb. 

Maximum  allowable 
Working  Pressure, 

Zero 
to 

Over  25 

to 

Over  50 
to 

Over  100 
to 

Over  150 
to 

Over  200 
Lb. 

Lb.  per  Sq.  In. 

25  Lb. 

50  Lb. 

100  Lb. 

150  Lb. 

200  Lb. 

Diameter 

Area 

of  Valve, 

of  Valve, 

Area  of  Grate,  Sq.  Ft. 

In. 

Sq.  In. 

1 

0.7854 

2.00 

2.50 

2.75 

3.25 

3.5 

3.75 

IK 

1.2272 

3.25 

4.00 

4.25 

5.00 

5.5 

5.75 

1H 

1.7671 

4.50 

5.50 

6.00 

7.25 

8.0 

8.50 

2 

3.1416 

8.00 

9.75 

10.75 

13.00 

14.0 

15.00 

2J4 

4.9087 

12.50 

15.00 

16.50 

20.00 

22.0 

23.00 

3 

7.0686 

17.75 

21.50 

24.00 

29.00 

31.5 

33.25 

3-4 

9.6211 

24.00 

29.50 

32.50 

39.50 

43.0 

45.25 

4 

12.5660 

31.50 

38.25 

42.50 

51.50 

56.0 

59.00 

4M 

15.9040 

40.00 

48.50 

53.50 

65.00 

71.0 

74.25 

one-tenth  of  the  nominal  diameter  of  the  seat  when  there  is  no  pres- 
sure on  the.  boiler.  A  relief  valve  used  on  a  hot-water  heating  boiler 
need  not  have  a  lifting  device. 

357  Every  safety  valve  or  water  relief  valve  shall  have  plainly 
stamped  on  the  body  or  cast  thereon  the  manufacturer's  name  or 
trade  mark  and  the  pressure  at  which  it  is  set  to  blow.    The  seats  and 
discs  of  safety  or  water  relief  valves  shall  be  made  of  non-ferrous 
material. 

358  The  minimum  size  of  safety  or  water  relief  valve  or  valves 
for  each  boiler  shall  be  governed  by  the  grate  area  of  the  boiler,  a? 
shown  by  Table  9. 


NEW  INSTALLATIONS,   PART  I,   SECTION  II,   HEATING   BOILERS         85 

When  the  conditions  exceed  those  on  which  Table  9  is  based,  the 
following  formula  for  bevel  aiid  flat  seated  valves  shall  be  used  : 

FX70 
A  =       -p—  Xll 

in  wliich 

A  =  area  of  direct  spring-loaded  safety  valve  per  square  foot 
of  grate  surface,  sq.  in. 

W  =  weight  of  water  evaporated  per  square  foot  of  grate  sur- 
face per  second,  Ib. 

P  =  pressure  (absolute)  at  which  the  safety  valve  is  set  to 
blow,  Ib.  per  sq.  in. 

359  Double    Grate  Down  Draft  Boilers.     In   determining  the 
number  and  size  of  safety'  valves  or  water  relief  valves  the  grate  area 
shall  equal  the  area  of  the  upper  grate  plus  one-half  of  the  area  of 
the  lower  grate. 

360  Boilers  Fired  With  Oil  or  Gas.    In  determining  the  number 
and  size  of  safety  or  water  relief  valve  or  valves  for  a  boiler  using  gas 
or  liquid  fuel,  15  sq.  ft.  of  heating  surface  shall  be  equivalent  to  one 
square  foot  of  grate  area.     If  the  size  of  grate  for  use  of  coal  is  evi- 
dent from  the  boiler  design,  such  size  may  be  the  basis  for  the  de- 
termination of  the  safety  valve  capacity. 

STEAM  AXD  WATER  GAGES 

361  Steam  Gages.     Each  steam  boiler  shall  have  a  steam  gage 
connected  to  the  steam  space  or  to  the  water  column  or  its  steam 
connection.      The   steam  gage   shall   be   connected   to   a   syphon   or 
equivalent  device  of  sufficient  capacity  to  keep  the  gage  tube  filled 
with  water  and  so  arranged  that  the  gage  cannot  be  shut  off  from  the 
boiler  except  by  a  cock  placed  near  the  gage  and  provided  witli  a  tee 
or  lever  handle  arranged  to  be  parallel  to  the  pipe  in  which  it  is  lo- 
cated when  the  cock  is  open.     Connections  to  gages  shall  be  of  brass, 
copper  or  bronze  composition.     The  dial  of  a  steam  gage  for  a  steam 
heating  boiler  shall  be  graduated  to  not  less  than  30  Ib. 

36i2  Pressure  or  Altitude  Gages.  Each  hoi-water  boiler  shall 
have  a  gage  connected  in  such  a  manner  that  it  cannot  be  shut  off 
from  the  boiler  except  by  a  cock  with  tee  or  lever  handle,  placed  on  the 
pipe  near  the  gage.  The  handle  of  the  cock  shall  be  parallel  to  the  pipe 
in  which  it  is  located  when  the  cock  is  open.  Connections  to  gages 
shall  be  made  of  brass,  copper  or  bronze  composition.  The  dial  of 


S6  REPORT  OP  BOILER  CODE  COMMITTEE,  AM.SOC.M.E. 

the  pressure  or  altitude  gage  shall  he  graduated  to  not  less  than  li/> 
times  the  maximum  allowable  working  pressure. 

363  Thermometers.     Each   hot-water  boiler  shall  have   a  ther- 
mometer so  located  and  connected  that  it  shall  be  easily  readable  when 
observing  the  water  pressure  or  altitude.     The  thermometer  shall  be 
so  located  that  it  shall  at  all  times  indicate  the  temperature  in  deg. 
fahr.,  of  the  water  in  the  boiler. 

FITTINGS  AND  APPLIANCES 

364  Bottom  Blow-off  Pipes.     Each  boiler  shall  have  a  blow-off 
pipe,  fitted  with  a  valve  or  cock,  in  direct  connection  with  the  lowest 
water  space  practicable. 

365  Damper  Regulators.     When  a  pressure  damper  regulator  is 
used,  the  boiler  pressure  pipe  shall  be  connected  to  the  steam  space  of 
the  boiler. 

366  Water  Glasses.     Each  steam  boiler  shall  have  one  or  more 
water  glasses. 

367  Gage  Cocks.    Each  steam  boiler  shall  have  two  or  more  gage 
cocks  located  within  the  range  of  the  visible  length  of  the  water  glass. 

368  Water  Column  Pipes.     The  minimum  size  of  pipes  connect- 
ing the  water  column  of  a  boiler  shall  be  1  in.     Water-glass  fittings 
•or  gage  cocks  may  be  connected  direct  to  the  boiler.    The  steam  con- 
nection to  the  water  column  of  a  horizontal  return  tubular  boiler 
shall  be  taken  from  the  top  of  shell  or  the  upper  part  of  the  head ;  the 
water  connection  shall  be  taken  from  a  point  not  less  than   6  in.  below 
the  center  line  of  the  shell.     Ko  connections,  except  for  damper  regu- 
lator, drains  or  steam  gages,  shall  be  placed  on  the  pipes  connecting 
a  water  column  to  a  boiler. 

METHODS  or  SETTING 

369  Wet-bottom  steel  plate  boilers  shall  have  a  space  of  not  less 
than  12  in.  between  the  bottom  of  the  boiler  and  the  floor  line  with 
access  for  inspection. 

370  Access  Doors.     The  minimum  size  of  access  door  used  in 
boiler  settings  shall  be   12   X    16  in.  or  equivalent  area,  the  least 
dimension  being  11  in. 

371  The    longitudinal    joints    of    a    horizontal    return    tubular 
boiler  shall  be  located  above  the  fire-line. 


NEW  INSTALLATIONS,  PART  I,  SECTION  II,  HEATING  BOILERS      87 
HYDROSTATIC  TESTS 

373  A  shop  test  of  60  Ib.  per  sq.  in.  hydrostatic  pressure  shall  be 
applied  to  steel  or  cast-iron  boilers  or  to  the  sections  of  cast-iron 
boilers  which  are  used  exclusively  for  low  pressure  steam  heating. 

373  Hot-water  boilers  for  a  maximum  allowable  working  pressure 
not  exceeding  30  Ib.  per  sq.  in.  used  exclusively  for  heating  buildings 
or  for  hot-water  supply,  when  constructed  of  cast-iron,  or  of  cast-iron 
excepting  the  connecting  nipples  and  bolts,  shall  be  subjected  to  a 
shop  test  of  60  Ib.  per  sq.  in.  hydrostatic  pressure  applied  to  the  boiler 
or  the  sections  thereof. 

374  A  maximum  allowable  working  pressure  in  excess  of  30  Ib. 
per  sq.  in.  will  be  allowed  on  a  hot-ivater  boiler  constructed  of  cast- 
iron,  or  of  cast-iron  excepting  the  connecting  nipples  and  bolts,  used 
exclusively  for  heating  buildings  or  for  hot-water  supply,  provided 
such  boilers  or  their  sections  have  been  subjected  to  a  shop  hydrostatic 
test  of  two  and  one-lialf  times  the  actual  working  pressure. 

375  Individual  shop  inspection  shall  be  required  only  for  boilers 
which  come  under  the  rules  for  power  boilers. 

STAMPING 

376  Each  plate  of  a  completed   boiler  shall  show  a  sufficient 
portion  of  the  plate  maker's  stamp  for  identification. 

377  Name.     All  boilers  referred  to  in  this  section  shall  be  plainly 
and  permanently  marked  with  the  manufacturer's  name  and  the  maxi- 
mum allowable  working  pressure. 


PART  II-EXISTING  INSTALLATIONS 

MAXIMUM  ALLOWABLE  WORKIXG  PRESSURE 


378  The  maximum  allowable  working  pressure  on  the  shell  of  a 
boiler  or  drum  shall  be  determined  by  the  strength  of  the  weakest 
course,  computed  from  the  thickness  of  the  plate,  the  tensile  strength 
of  the  plate,  the  efficiency  of  the  longitudinal  joint,  the  inside  diame- 
ter of  the  course  and  the  factor  of  safety  allowed  by  these  Rules. 


=  maximum  allowable  working  pressure,  Ib.  per  sq.  in. 

where 

TS  =  ultimate  tensile  strength  of  shell  plates,  Ib.  per  sq.  in. 
t  =  thickness  of  shell  plate,  in  weakest  course,  in. 

E  =  efficiency  of  longitudinal  joint,  method  of  determining 
which  is  given  in  Par.  181,  of  these  Rules 

R  —  inside  radius  of  the  weakest  course  of  the  shell  or  drum, 
in. 

FS  =  factor  of  safety  allowed  by  these  Rules 

379  Boilers  in  service  one  year  after  these  Rules  become  effective 
shall  be  operated  with  a  factor  of  safety  of  at  least  4  by  the  formula, 
Par.  378.    Five  years  after  these  Rules  become  effective,  the  factor  of 
safety  shall  be  at  least  4.5.    Tn  no.  case  shall  the  maximum  allowable 
working  pressure  on  old  boilers  be  increased,  unless  they  are  being 
operated  at  a  lesser  pressure  than  would  be  allowable  for  new  boilers, 
in  which  case  the  changed  pressure  shall  not  exceed  that  allowable  for 
new  boilers  of  the  same  construction. 

380  The  age  limit  of  a  horizontal  return  tubular  boiler  having  a 
longitudinal  lap  joint  and  carrying  over  50  Ib.  pressure  shall  be  20 
years,  except  that  no  lap  joint  boiler  shall  be  discontinued  from  serv- 
ice solely  on  account  of  age  until  5  years  after  these  Rules  become 
effective. 

89 


DO 


REPORT  OF  BOILER  CODE  COMMITTEE,  AM.ROC.M.E. 


381  Second-hand  boilers,  by  which  arc  meant  boilers  where  both 
the  ownership  and  location  arc  changed,  shall  have  a  factor  of  safety 
of  at  least  5%,  by  the  formula  Par.  378,  one  year  after  these  Eules 
become  effective,  unless  constructed  in  accordance  with  the  Eules  con- 
tained in  Part  I,  when  the  factor  shall  be  at  least  5. 

38.2  Cast-iron  Headers  and  Mud  Drums.  The  maximum  allow- 
able working  pressure  on  a  water  tube  boiler,  the  tubes  of  which  are 
secured  to  cast-iron  or  malleable  iron  headers,  or  which  have  cast-iron 
mud  drums,  shall  not  exceed  160  Ib.  per  sq.  in. 

383  Fleam  Heating  Boilers.     The  maximum  allowable  working 
pressure  shall  not  exceed  15  Ib.  per  sq:  in.  on  a  boiler  used  exclusively 
for  low  pressure  steam  heating. 

384  No  pressure  shall  be  allowed  on  a  boiler  on  which  a  crack 
is  discovered  along  the  longitudinal  riveted  joint. 

STREXGTI-I  OF  MATERIALS 

385  Tensile  Strength.     When   the  tensile  strength  of  steel  or 
wrought-iron  shell  plates  is  not  known,  it  shall  be  taken  as  55,000  Ib. 
per  sq.  in.  for  steel  and  45,000  Ib.  for  wrought-iron. 

386  Strength  of  Rivets  in  Shear.     In  computing  the  ultimate 
strength  of  rivets  in  shear  the  following  values  in  pounds  per  square 
inch  of  the  cross-sectional  area  of  the  rivet  shank  shall  be  used : 

Iron  rivets  in  single  shear 38,000 

Iron  rivets  in  double  shear 76,000 

Steel  rivets  in  single  shear 44,000 

Steel  rivets  in  double  shear 88,000 

The  cross-sectional  area  shall  be  that  of  the  rivet  shank  after  driving. 

387  Crushing  Strength  of  Mild  Steel.     The  resistance  to  crush- 
ing of  mild  steel  shall  be  taken  at  95,000  Ib.  Der  sq.  in.  of  cross- 
sectional  area. 

TABLE  10    SIZES  OF  RIVETS  BASED  ON  PLATE  THICKNESS 


Thickness  of  plate 

1A" 

A" 

A" 

H" 

H* 

H" 

Diameter  of  rivet  after  driving  

W 

H" 

w 

H' 

H* 

W 

Thickness  of  plate  

A" 

»* 

w 

&* 

H* 

__ 

Diameter  of  rivet  after  driving  

H* 

*r 

«* 

itf 

iA* 

— 

388  Rivets.*  When  the  diameter  of  the  rivet  holes  in  the  longi- 
tudinal joints  of  a  boiler  is  not  known,  the  diameter  and  cross-sectional 
area  of  rivets,  after  driving  may  be  ascertained  from  Table  10,  or  by 
cutting  out  one  rivet  in  the  body  of  the  joint. 


EXISTING  INSTALLATIONS,  PART  II  91 

SAFETY  VALVES  FOR  POWER  BOILERS 

389  The  safety  valve  capacity  of  eacli  boiler  shall  be  such  that 
tho  safety  valve  or  valves  will  discharge  all  the  steam  that  can  be 
generated  by  the  boiler  without  allowing  the  pressure  to  rise  more 
than  6  per  cent  above  the  maximum  allowable  working  pressure,  or 
more  than  6  per  cent  above  the  highest  pressure  to  which  any  valve  is 
set. 

390  One  or  more  safety  valves  on  every  boiler  shall  be  set  at  or 
below   the   maximum   allowable   working   pressure.      The   remaining 
valves  may  be  set  within  a  range  of  3  per  cent  above  the  maximum 
allowable  working  pressure,  but  the  range  of  setting  of  all  .of  the 
valves  on  a  boiler  shall  not  exceed  10  per  cent  of  the  highest  pressure 
to  which  any  valve  is  set. 

391  Safety  valve  capacity  may  be  checked  in  any  one  of  three 
different  ways,  and  if  found  sufficient,  additional  capacity  need  not  be 
provided : 

a  By  making  an  accumulation  test,  by  shutting  off  all  other 
steam  discharge  outlets  from  the  boiler  and  forcing  the 
fires  to  the  maximum.  The  safety  valve  equipment  shall 
be  sufficient  to  prevent  an  excess  pressure  beyond  6  per 
cent  as  specified  in  Par.  389. 

b  By  measuring  the  maximum  amount  of  fuel  that  can  be 
burned  and  computing  the  corresponding  evaporative  ca- 
pacity upon  the  basis  of  the  heating  value  of  the  fuel.  See 
Appendix,  Pars.  421  to  427. 

c  By  determining  the  maximum  evaporative  capacity  by 
measuring  the  feedwater.  The  sum  of  the  safety  valve 
capacities  shall  be  equal  to  or  greater  than  the  maximum 
evaporative  capacity  of  the  boiler. 

392  In  case  either  of  the  methods  outlined  in  sections  I  or  c  of 
Par.  391  is  employed,  the  safety  valve  capacities  shall  be  taken  at  the 
maximum  values  given  in  Table  8  for  spring  loaded  pop  safety  valves, 
or  0.66  times  the  maximum  values  given  in  Table  8,  for  lever  safety 
valves. 

393  When  additional  valve  capacity  is  required,  any  valves  added 
shall  conform  to  the  requirements  in  Part  I  of  these  Rules. 

394  Xo  valve  of  any  description   shall  be  placed  between   the 
safety  valve  and  the  boiler,  nor  on  the  discharge  pipe  between  the 
safety  valve  and  the  atmosphere.    When  a  discharge  pipe  is  used,  it 


92  REPORT  OF  BOILER  CODE  COMMITTEE,  AM.SOC.M.E. 

shall  be  not  less  than  the  full  size  of  the  valve,  and  the  discharge  pipe 
shall  be  fitted  with  an  open  drain  to  prevent  water  lodging  in  the 
upper  part  of  the  safety  valve  or  in  the  pipe.  If  a  muffler  is  used  on 
a  safety  valve  it  shall  have  sufficient  outlet  area  to  prevent  back 
pressure  from  interfering  with  the  proper  operation  and  discharge 
capacity  of  the  valve.  The  muffler  plates  or  other  devices  shall  be  so 
constructed  as  to  avoid  any  possibility  of  restriction  of  the  steam 
passages  due  to  deposit.  When  an  elbow  is  placed  on  a  safety  valve 
discharge  pipe,  it  shall  be  located  close  to  the  safety  valve  outlet  or 
the  pipe  shall  be  securely  anchored  and  supported.  All  safety  valve 
discharges  shall  be  so  located  or  piped  as  to  be  carried  clear  from 
running  boards  or  working  platforms  used  in  controlling  the  main 
stop  valves  of  boilers  or  steam  headers. 

* 

FITTINGS  AND  APPLIANCES 

396  Water  Glasses  and  Gage  Cocks.  Each  steam  boiler  shall  have 
at  least  one  water  glass,  the  lowest  visible  part  of  which  shall  be  not 
less  than  2  in.  above  the  lowest  permissible  water  level. 

396  Each  boiler  shall  have  three  or  more  gage  cocks,  located  with- 
in the  range  of  the  visible  length  of  the  water  glass,  when  the  maxi- 
mum allowable  working  pressure  exceeds  15  Ib.  per  sq.  in.,  except  when 
such  boiler  has  two  water  glasses  with  independent  connections  to  the 
boiler,  located  on  the  same  horizontal  line  and  not  less  than  2  ft.  apart. 

397  No  outlet  connections,  except  for  damper  regulator,  feed- 
water  regulator,  drains  or  steam  gages,  shall  be  placed  on  the  pipes 
connecting  a  water  column  to  a  power  boiler. 

398  Steam  Gages.     Each  steam  boiler  shall  have  a  steam  gage 
connected  to  the  steam  space  or  to  the  water  column  or  to  its  steam 
connection.    The  steam  gage  shall  be  connected  to  a  syphon  or  equiva- 
lent device  of  sufficient  capacity  to  keep  the  gage  tube  filled  with 
water  and  so  arranged  that  the  gage  cannot  be  shut  off  from  the 
boiler  except  by  a  cock  placed  near  the  gage  and  provided  with  a  tee 
or  lever  handle  arranged  to  be  parallel  to  the  pipe  in  which  it  is 
located  when  the  cock  is  open.    Connections  to  gages  shall  be  of  brass, 
copper  or  bronze  composition. 

399  Stop  Valves.     Each  steam  outlet  from  a  power  boiler  (except 
safety  valve  connections)  shall  be  fitted  with  a  stop  valve  located  as 
close  as  practicable  to  the  boiler. 

400  When  a  stop  valve  is  so  located  that  water  can  accumulate, 
ample  drains  shall  be  provided. 


EXISTING   INSTALLATIONS,   PART   II  03 

401  Bottom  Bloiv-Off  Pipes.     Each  boiler  shall  have  a  blow-off 
pipe  fitted  with  a  valve  or  cock,  in  direct  connection  with  the  lowest 
water  space  practicable. 

402  When  the  maximum  allowable  working  pressure  exceeds  125 
Ib.  per  sq.  in.,  the  blow-off  pipe  shall  be  extra  heavy  from  boiler  to 
valve  or  valves,  and  shall  run  full  size  without  reducers  or  bushings. 
All  fittings  between  the  boiler  and  valve  shall  be  steel,  extra  heavy 
malleable  iron  or  extra  heavy  cast-iron. 

403  When  the  maximum  allowable  working  pressure  exceeds  125 
Ib.  per  sq.  in.,  each  bottom  blow-off  pipe  shall  be  fitted  with  an  extra 
heavy  valve  or  cock.     Preferably  two   (2)   valves,  or  a  valve  and  a 
cock  should  be  used  on  each  blow-off  in  which  case  such  valves,  or 
valve  and  cock,  shall  be  extra  heavy. 

404  A  bottom  blow-off  pipe  when  exposed  to  direct  furnace  heat, 
shall  be  protected  from  the  products  of  combustion  by  fire-brick,  a 
substantial  cast-iron  removable  sleeve,  or  a  covering  of  non-conducting 
material. 

405  An  opening  in  the  boiler  setting  for  a  blow-off  pipe  shall  be 
arranged  to  provide  for  free  expansion  and  contraction. 

406  Feed  Piping.     The  feed  pipe  of  a  steam  boiler  operated  at 
more  than  15  Ib.  per  sq.  in.  maximum  allowable  working  pressure, 
shall  be  provided  with  a  check  valve  near  the  boiler  and  a  valve  or  cock 
between  the  check  valve  and  the  boiler,  and  when  two  or  more  boilers 
are  fed  from  a  common  source,  there  shall  also  be  a  globe  valve  on  the 
branch  to  each  boiler,  between  the  check  valve  and  the  source  of  supply. 
When  a  globe  valve  is  used  on  a  feed  pipe,  the  inlet  shall  be  under  the 
disc  of  the  valve. 

407  Lamphreyt  Fronts.     Each   boiler   fitted   with   a   Lamphrey 
boiler  furnace  mouth  protector,  or  similar  appliance,  having  valves  on 
the  pipes  connecting  them  to  the  boiler,  shall  have  these  valves  locked 
or  sealed  open.    -Such  valves,  when  used,  shall  be  of  the  straightway 
type. 

HYDROSTATIC  PRESSURE  TESTS 

408  Test  Pressure.     When  a  hydrostatic  test  is  applied  the  re- 
quired test  pressure  shall  be  one  and  one-half  times  the  maximum  al- 
lowable working  pressure.    The  pressure  shall  be  under  proper  control 
so  that  in  no  case  shall  the  required  test  pressure  be  exceeded  by  more 
than  2  per  cent. 

409  During  a  hydrostatic  test  of  a  boiler,  the  safety  valve  or 
valves  shall  be  removed  or  each  valve  disc  shall  be  held  to  its  seat  by 
means  of  a  testing  clamp  and  not  by  screwing  down  the  compression 
screw  upon  the  spring. 


APPENDIX 


EFFICIENCY  OF  JOINTS 

410     Efficiency  of  Riveted  Joints.     The  ratio  which  the  strength 
of  a  unit  length  of  a  riveted  joint  has  to  the  same  unit  length  of 
the  solid  plate  is  known  as  the  efficiency  of  the  joint  and  shall  be 
calculated  by  the  general  method  illustrated  in  the  following  examples : 
TS  =  tensile  strength  stamped  on  plate,  Ib.  per  sq.  in. 
t  =  thickness  of  plate,  in. 
I  =  thickness  of  butt  strap,  in. 

P  =  pitch  of  rivets,  in.,  on  row  having  greatest  pitch 
d  =  diameter  of  rivet  after  driving,  in.  =  diameter  of  rivet 
hole 


© 
©   rp>j 

**©  4>  0  ©  ©  © 

© 

FIG.  21     EXAMPLE  OF  LAP  JOINT,  LONGITUDINAL 
OR  CIRCUMFERENTIAL,  SINGLE-KIVETED 


a  =  cross-sectional  area  of  rivet  after  driving,  sq.  in. 

s  =  shearing  strength  of  rivet  in  single  shear,  Ib.  per  sq.  in., 

as  given  in  Par.  16 
8  =  shearing  strength  of  rivet  in  double  shear,  Ib.  per  sq.  in., 

as  given  in  Par.  16 
c  =  crushing  strength  of  mild  steel,  Ib.  per  sq.  in.,  as  given 

in  Par.  15 

n  =  number  of  rivets  in  single  shear  in  a  unit  length  of  joint 
N  =  number  of  rivets  in  double  shear  in  a  unit  length  of  joint. 


RETORT  OF  BOILER  CODE  COMMITTEE,  AM.SOC.M.E. 


411     Example:  Lap  joint,  longitudinal  or  circumferential,  single- 
riveted. 

A  =  strength  of  solid  plate  =  PXtXTS 

B  =  strength  of  plate  beween  rivet  holes  =  (P — d)tX TS 

C  =  shearing  strength  of  one  rivet  in  single  shear  =  nXsXa 

D  =  crushing  strength  of  plate  in  front  of  one  rivet  =  dXlXc 

Divide  B,  C  or  D  (whichever  is  the  least)  by  A,  and  the  quotient  will  be  the 

efficiency  of  a  single-riveted  lap  joint  as  shown  in  Fig.  21. 


TS  =  55,000  Ib.  per  sq.  in. 
*  =  i^  in.  =0.25  in. 
P  =  l%  in.  =  1.625  in. 
d  =  H  in.  =0.6875  in. 
a  =0.3712  sq.  in. 
s  =  44,OC01b.  persq.  in. 


c =95,000  Ib.  per  sq.  in. 
A  =  1.625  X  0.25  X  55,000  =22,343 
B  =  (1.625—0.6875)  0.25X55,000  =  12,890 
C  =  1  X44,000  X0.3712  =  16,33^ 
D  =  0.6875  X0.25  X  95,000  =  16,328 


©           K--P  -** 

'©    <$>    4>    o    © 
©      ©    ©    ©  / 

© 

j^  , 

FIG.  22     EXAMPLE  OF  LAP  JOINT,  LONGITUDINAL 
OR  CIRCUMFERENTIAL,  DOUBLE-EIVETED 


12,890  (B) 


=0.576  =  efficiency  of  joint 


22,343  (A) 
Example :  Lap  joint,  longitudinal  or  circumferential,  double- 


412 
riveted. 

A  =  strength  of  solid  plate  =  PXtXTS 

B  =  strength  of  plate  between  rivet  holes  =  (P — d)  t  X  TS 

C  =  shearing  strength  of  two  rivets  in  single  shear  =  n  X  s  X  a  i 

D  =  crushing  strength  of  plate  in  front  of  two  rivets  =nXdXtXc 

Divide  B,  C  or  D  (whichever  is  the  least)  by  A,  and  the  quotient  will  be  C 

efficiency  of  a  double-riveted  lap  joint,  as  shown  in  Fig.  22. 


TS  =  55,000  Ib .  per  sq.  in. 
t  =  &  in.  =0.3125  in. 
p=27^in.=2.875in. 
d  =  %  in.  =0.75  in. 
o=0. 4418  sq.  in. 
s=  44,000  Ib.  persq.  in. 


c  =95,000  Ib.  per  sq.  in. 
A  =2.875X0.3125X55,000  =  49,414 
B  =  (2.875—0.75)  0.3125 X55,000 =36,523 
C  =2  X  44,000  X  0.44 18  =38,878 
D  =2  X0.75  X0.3125  X  95,000  -44,531 


=0.739  =  efficiency  of  joint 


APPENDIX  97 

413     Example:    Butt  and  double  strap  joint,  double-riveted. 

A  =  strength  of  solid  plate  =PXtXTS 

B  =  strength  of  plate  between  rivet  holes  in  the  outer  row  =  (P — d)  t  X  TS 

C  =  shearing  strength  of  two  rivets  in  double  shear,  plus  the  shearing  strength  of 
one  rivet  in  single  shear  =NXSXa+nXsXa 

D  =  strength  of  plate  between  rivet  holes  in  the  second  row,  plus  the  shearing 
strength  of  one  rivet  in  single  shear  in  the  outer  row  =  (P — 2d)  t  X  TS 
-fnXsXa 


FIG.  23     EXAMPLE  OF  BUTT  AND  DOUBLE  STRAP 
JOINT,  DOUBLE-KIVETED 


E  =  strength  of  plate  between  rivet  holes  in  the  second  row,  plus  the  crushing 
strength  of  butt  strap  in  front  of  one  rivet  in  the  outer  row  =  (P — 2d)  t 
XTS+dXbXc 

F  =  crushing  strength  of  plate  in  front  of  two  rivets,  plus  the  crushing  strength 
of  butt  strap  in  front  of  one  rivet  =NXdXtXc+nXdXbXc 

G  =  crushing  strength  of  plate  in  front  of  two  rivets,  plus  the  shearing  strength 
of  one  rivet  in  single  she&r=NXdXtXc+nXsXa 

H  ^=  strength  of  butt  straps  between  rivet  holes  in  the  inner  row  =  (P — 2d)  2b 
X  TS.  This  method  of  failure  is  not  possible  for  thicknesses  of  butt  straps 
required  by  these  Rules  and  the  computation  need  only  be  made  for  ol  1 
boilers  in  which  thin  butt  straps  have  been  used.  For  this  reason  thL 
method  of  failure  will  not  be  considered  in  other  joints. 

Divide  B,  C,  D,  E,  F,  G  or  H  (whichever  is  the  least)  by  A,  and  the  quotient  will 


98  REPORT  OF  BOILER  CODE  COMMITTEE,  AM.SOC.M.E. 

be  the  efficiency  of  a 'butt  a/nd  double  strap  joint,  double-riveted,  as  shown  in 
Fig.  23. 

TS  =  55,000  Ib.  per  sq.  in.  a  =0.6013  sq.  in. 

t  =    y%  in.  =0.375  in.  s  =44,000  Ib.  per  sq.  in. 

b=   ^  m.  =0.3125  in.  £  =  88,000  Ib.  per  sq.  in. 

P=47/s  in.  =4.875  in.  c  =  95,000  Ib.  per  sq.  in. 
d=   y8  in.  =  0.875  in. 

Number  of  rivets  in  single  shear  in  a  unit  length  of  joint  =  1. 
Number  of  rivets  in  double  shear  in  a  unit  length  of  joint  =2. 


FIG.  24    EXAMPLE  OF  BUTT  AND  DOUBLE  STRAP  JOINT,  TRIPLE-EIVETED 


A  =4.875  X0.375  X55,000  =  100,547 

B  =  (4.875—  0.875)  0.375X55,000=82,500 

0=2X88,000X0.6013  +  1X44,000X0.6013  =  132,286 

D  =  (4.875—  2  X0.875)  0.375  X55,000  +  l  X44,000  X0.6013  =90,910 

E  =  (4.875—  2X0.875)0.375X55,000+0.875X0.3125X95,000=90,429 

F  =2  X0.875  X0.375  X  95,000  +0.875  X0.3125  X95,000  =  88,320 

G  =2  X0.875  X0.375  X  95,000  +1X44,000  X0.6013  =  88,800 


of  joint 


414     Example:    Butt  and  double  strap  joint,  triple-riveted. 
A  =  strength  of  solid  plate  =  PXtXTS 

B  =  strength  of  plate  between  rivet  holes  in  the  outer  row  =  (P— d]  t  X  TS 
C=  shearing  strength  of  four  rivets  in  double  shear,  plus  the  shearing  strength 

of  one  rivet  in  single  shear  =  NXSXa+nXsXa    • 
D= strength  of  plate  between  rivet  holes  in  the  second  row,  plus  the  shearing 

strength  of  one  rivet  in  single  shear  in  the  outer  row  =  (P— 2d)  t  X  TS 

+nXsXa 


APPENDIX  99 

E  =  strength  of  plate  between  rivet  holes  in  the  second  row,  plus  the  crushing 
strength  of  butt  strap  in  front  of  one  rivet  in  the  outer  row  =  (P — 2d)  t 
XTS+dXbXc 

F  =  crushing  strength  of  plate  in  front  of  four  rivets,  plus  the  crushing  strength 
of  butt  strap  in  front  of  one  rivet  =  NXdXtXc+nXdXbXc 

C  =  crushing  strength  of  plate  in  front  of  four  rivets,  plus  the  shearing  strength 
of  one  rivet  in  single  shear  =  NXdXtXc-\-nXsXa 

Divide  B,  C,  D,  E,  F  or  G  (whichever  is  the  least)  by  A,  and  the  quotient  will 
be  the  efficiency  of  a  butt  and  double  strap  joint,  triple-riveted,  as  shown  in  Fig.  24. 

TS=  55,000  Ib.  per  sq.  in.  a  =  0.5185  sq.  in. 

t  =    H  in.  =0.375  in.  s  =44,000  Ib.  per  sq.  in. 

I  =    ^  in.  =0.3125  in.  S  =  88,000  Ib.  per  sq.  in. 

P  =  6}^  in.  =6. 5  in.  c=  95,000  Ib.  per  sq.  in. 
d=    if  in.  =0.8125  in. 

Number  of  rivets  in  single  shear  in  a  unit  length  of  joint  =  1. 
Number  of  rivets  in  double  shear  in  a  unit  length  of  joint  =4. 

A  =6.5X0.375X55,000  =  134,062 

B  =  (6.5—0.8125)  0.375 X55,000  =  117,304 

C  =4  X88,000  X0.5185  + 1  X44,000  X0.5185  =205,326 

D  =  (6.5—2  X0.8125)  0.375  X 55, 000+1 X 44,000  X0.5185  =  123,360 

E  =  (6.5— 2X0.8125)  0.375X55,000+0.8125X0.3125X95,000  =  124,667 

F  =4 X0.8125 X0.375 X95,000  +  l  X0.8125 X0.3125 X95,000  =  139,902 

(2=4X0.8125X0.375X95,000+1X44,000X0.5185  =  138,595 

117,304  (5) 

134,062  W)  =0-^5  =  efficiency  of  joint 

415     Example:  Butt  and  double  strap  joint,  quadruple-riveted. 

A  =  strength  of  solid  plate  =  PXtXTS 

B  =  strength  of  plate  between  rivet  holes  in  the  outer  row  =  (P — d)  t  X  TS 

C  =  shearing  strength  of  eight  rivets  in  double  shear,  plus  the  shearing  strength 
of  three  rivets  in  single  shear  =  NXSXa-\-nXsXa 

D  =  strength  of  plate  between  rivet  holes  in  the  second  row,  plus  the  shearing 
strength  of  one  rivet  in  single  shear  in  the  outer  row  =  (P — 2d)  tXTS 
+!XsXa 

E  =  strength  of  plate  between  rivet  holes  in  the  third  row,  plus  the  shearing 
strength  of  two  rivets  in  the  second  row  in  single  shear  and  one  rivet  in 
single  shear  in  the  outer  row  =  (P— 4d)  tXTS+nXsXa 

F—  strength  of  plate  between  rivet  holes  in  the  second  row,  plus  the  crushing 
strength  of  butt  strap  in  front  of  one  rivet  in  the  outer  row  =  (P — 2d)  t 
XTS+dXbXc 


100 


REPORT  OF  BOILER  CODE  COMMITTEE,  AM.SOC.M.E. 


G=  strength  of  plate  between  rivet  holes  in  the  third  row,  plus  the  crushing 

strength  of  butt  strap  in  front  of  two  rivets  in  the  second  row  and  one 

rivet  in  the  outer  row  =  (P — 4d)  IXTS+nXdXbXc 
H=  crushing  strength  of  plate  in  front  of  eight  rivets,  plus  the  crushing  strength 

of  butt  strap  in  front  of  three  rivets  =NXdXtXc+nXdXbXc 
7=  crushing  strength  of  plate  in  front  of  eight  rivets,  plus  the  shearing  strength 

of  two  rivets  hi  the  second  row  and  one  rivet  in  the  outer  row,  in  single 

shear  =  NXdXtXc+nXsXa 

Divide  B,  C,  D,  E,  F,  G,  H  or  /  (whichever  is  the  least)  by  A,  and  the  quotient 
will  be  the  efficiency  of  a  butt  and  double  strap  joint  quadruple-riveted,  as  shown 
in  Fig.  25. 


vj|y  t£)  v^7~~ 


FIG. 


EXAMPLE  OF  BUTT  AND  DOUBLE  STRAP  JOINT,  QUADRUPLE-KIVETED 


TS  =  55,000  Ib.  per  sq.  in.  a  =  0.6903  sq.  in. 

t=     %  in.  =0.5  in.  s  =44,000  Ib.  per  sq.  in. 

6  =     i^  in.  =0.4375  in.  S  =  88,000  Ib.  per  sq.  in. 

P  =  15  in.  c  =95,000  Ib.  per  sq.  in. 

d=     H  in.  =0.9375  in. 

Number  of  rivets  in  single  shear  in  a  unit  length  of  joint  =3. 
Number  of  rivets  in  double  shear  in  a  unit  length  of  joint  =  8. 
A  =  15X0.5X55,000  =  412,500 
B  =  (15— 0.9375)  0.5X55,000  =  386,718 
C  =  8  X  88,000  X  0.6903  +3  X44,000  X0.6903  =  577,090 
D  =  (1^—2X0.9375)  0.5X55,000+1X44,000X0.6903=391,310 
E  =  (15—4  X0.9375)  0.5  X 55,000  +3  X44,000  X0.6903  =  400,494 
F  =  (15— 2X0.9375)0.5X55,000+0.9375X0.4375X95,000=399,902 
G  =  (15—4  X0.9375)  0.5  X55,000+3  X 0.9375  X 0.4375  X 95,000  =  426,269 
#  =  8X0.9375X0.5X95,000+3X0.9375X0.4375X95,000  =473,145 

7=8X0,9375X0.5X95,000+3X44,000X0.6903=447,369 


386,718  QB) 
412,500  (A) 


=0.937=  efficiency  of  joint 


APPENDIX 


101 


416     Example:  Butt  and  double  strap  joint,  quintuple-riveted.- 

A  -  strength  of  solid  plate  =  PXtXTS 

B  =  strength  of  plate  between  rivet  holes  in  the  outer  row  =  (P — d)  tXTS 

C=  shearing  strength  of  16  rivets  in  double  shear,  plus  the  shearing  strength  of 

seven  rivets  in  single  shear  =  N XSXa+nXsXa 
D  =  strength  of  plate  between  rivet  holes  in  the  second  row,  plus  the  shearing 

strength  of  one  rivet  in  single  shear  in  the  outer  row  =  (P— 2d)  tXT& 

+!XsXa 
E  =  strength  of  plate  between  rivet  holes  in  the  third  row,  plus  the  shearing 

strength  of  two  rivets  in  the  second  row  in  single  shear  and  one  rivet  in 

single  shear  in  the  outer  row  =  (P — 4d)  t  X  TS+3  Xs  Xa 


FIG.  26     EXAMPLE  OF  BUTT  AND  DOUBLE  STRAP  JOINT,  QUINTUPLE-EIVETED 


F  =  strength  of  plate  between  rivet  holes  in  the  fourth  row,  plus  the  shearing 
strength  of  four  rivets  in  the  third  row,  two  rivets  in  the  second  row  and 
one  rivet  in  the  outer  row  in  single  shear  =  (P — 8d)  t X TS+nXsXa 

G  =  strength  of  plate  between  rivet  holes  in  the  second  row,  plus  the  crushing 
strength  of  butt  strap  in  front  of  one  rivet  in  the  outer  row  =  (P — 2d)  t 
XTS+dXbXc 

H—  strength  of  plate  between  rivet  holes  in  the  third  row,  plus  the  crushing 
strength  of  butt  strap  in  front  of  two  rivets  in  the  second  row  and  one 
rivet  in  the  outer  row  =  (P— 4d)  tXTS -\-3XdXbXc 

1  =  strength  of  plate  between  rivet  holes  in  the  fourth  row,  plus  the  crushing 
strength  of  butt  strap  in  front  of  four  rivets  in  the  third  row,  two  rivets 
in  the  second  row  and  one  rivet  in  the  outer  row  =  (P — 3d)  tXTS+n 
XdXbXc 


102 


REPORT  OF  BOILER  CODE  COMMITTEE,  AM.SOC.M.E. 


J  =  crushing  strength  of  plate  in  front  of  16  rivets,  plus  the  crushing  strength  of 

butt  strap  in  front  of  seven  rivets  =  NXdXtXc+nXdXbXc 
K  =  crushing  strength  of  plate  in  front  of  16  rivets,  plus  the  shearing  strength 
of  four  rivets  in  the  third  row,  two  rivets  in  the  second  row  and  one  rivet 
in  the  outer  row  in  single  shear =NXdXtXc+nXsXa 

Divide  B,  C,  D,  E,  F,  G,  H,  I,  J  or  K  (whichever  is  the  least)  by  A,  and  the  quo- 
tient will  be  the  efficiency  of  a  butt  and  double  strap  joint,  quintuple-riveted,  as 
shown  in  Fig.  26  or  Fig.  27. 

TS  =  55,000  Ib.  per  sq.  in.  a  =  1.3529  sq.  in. 

t=    %in.  =0.75  in.  s=  44,000  Ib.  per  sq.  in. 

6=   Yz  in.  =0.5  in.  S  =  88,000  Ib.  per  sq.  in. 

P=36  in.  c  =  95,000  Ib.  per  sq.  in. 


P=  36- 


FIG.  27    EXAMPLE  OF  BUTT  AND  DOUBLE  STRAP  JOINT,  QUINTUPLE-RIVETED 

Number  of  rivets  in  single  shear  in  a  unit  length  of  joint  =7.  - 
Number  of  rivets  in  double  shear  in  a  unit  length  of  joint  =  16. 

A  =36  X0.75  X55,000  =  1,485,000 

B  =  (36—1.3125)  0.75  X55,000  =  1,430,860 

0  =  16X88,000X1.3529+7X44,000X1.3529=2,321,576 

D  =  (36—2  X  1.3125)  0.75 X55,000+l  X44,"000 X  1.3529  =  1,436,246 

#  =  (36^X1.3125)0.75X55,000+3X44,000X1.3529  =  1,447,020 
F  =  (36— 8X1.3125)  0.75X55,000+7X44,000X1.3529  =  1,468,568 
G  =  (36— 2X1.3125)0.75X55,000  +  1.3125X0.5X95,000  =  1,439,064 

#  =  (36— 4X1.3125)0.75X55,000+3X1.3125X0.5X95,000  =  1,455,472 
/  =  (36— 8X1.3125)0.75X55,000+7X1.3125X0.5X95,000  =  1,488,141 
J  =  16X1.3125X0.75X95,000+7X1.3125X0.5X95,000  =  1,932,266 

K  =  16  X  1.3125  X0.75  X95,000 +7  X44,000  X  1.3529  =  1,912,943 


1,430,860  (B) 
1,485,000  (A) 


=0.963  =  efficiency  of  joint 


APPENDIX 


103 


417  Figs.  .28  and  29  illustrate  other  joints  that  may  be  used. 
The  butt  and  double  strap  joint  with  straps  of  equal  width  shown  in 
Fig.  28  may  be  so  designed  that  it  will  have  an  efficiency  of  from  82 
to  84  per  cent  and  the  saw-tooth  joint  shown  in  Fig.  29  so  that  it  will 
have  an  efficiency  of  from  92  to  94  per  cent. 


FIG.  28     ILLUSTRATION  OF  BUTT  AND  DOUBLE  STRAP  JOINT  WITH  STRAPS  OF 

EQUAL  WIDTH 


FIG.  29    ILLUSTRATION  OF  BUTT  AND  DOUBLE  STRAP  JOINT  OF  THE  SAW-TOOTH 

TYPE 


104: 


REPORT  OF  BOILER  CODE  COMMITTEE,  AM.SOC.M.E. 


BRACED  AND  STAYED  SUKFACKS 

418  The  allowable  loads  based  on  the  net  cross-sectional  areas  of 
staybolts  with  Y-threads,  are  computed  from  the  following  formulae. 
The  use  of  Whitworth  threads  with  other  pitches  is  permissible. 

The  formula  for  the  diameter  of  a  staybolt  at  the  bottom  of  a 
Y-thread  is: 

D—  (P  X  1.^32)  =  d 
where 

D  =  diameter  of  staybolt  over  the  threads,  in. 
P  =  pitch  of  threads,  in. 

d  =  diameter  of  staybolt  at  bottom  of  threads,  in. 
1.73.2  =  a  constant 

When  IT.  ,S.  threads  are  used,  the  formula  becomes 
D  —  (P  X  1.732  X  0.75)  =  d 

Tables  11  and  12  give  the  allowable  loads  on  net  cross-sectional 
areas  for  staybolts  with  V-threads,  having  12  and  10  threads  per  inch. 


TABLE  11.    ALLOWABLE  LOADS  ON  STAYBOLTS  WITH  V-THREADS,  12  THREADS 

PER  INCH 


Outside  Diameter 
of 

Diameter  at 
Bottom  of 

Net  Cross- 
Sectional  Area 

Allowable  Load 
at  7500  Lb. 

Staybolts,  In. 

Thread, 
In. 

(at  Bottom  of 
Thread)  ,  Sq.  In. 

Stress,  per 
Sq.  In. 

*/t 

0.7500 

0  .  6057 

0.288 

2160 

ii 

0.8125 

0.6682 

0.351 

2632 

% 

0.8750 

0.7307 

0.419 

3142 

1A 

0.9375 

0.7932 

0.494 

3705 

,                  1 

.0000 

0.8557 

0.575 

4312 

Jj 

.0625 

0.9182 

0.662 

4965 

Lg 

.1250 

0.9807 

0.755 

5662 

•     I 

.1875 

1.0432 

0.855 

6412 

14 

.2500 

1  .  1057 

0.960 

7200 

JL. 

.3125 

1  .  1682 

1.072 

8040 

iHi 

.3750 

1.2307 

1.190 

8925 

1A 

.4375 

1.2932 

1.313 

9849 

IK 

.5000 

1  .  3557 

1.444 

10830 

APPENDIX 


105 


TABLE  12.    ALLOWABLE  LOADS  ON  STAYBOLTS  WITH  V-THREADS,  10  THREADS 

PER  INCH 


Outside  Diameter 
of 

Diameter  at 
Bottom 

Net  Cross- 
Sectional  Area 

Allowable  Load 
at  7500  Lb. 

Staybolts,  In. 

of  Thread, 
In. 

(at  Bottom  of 
Thread),  Sq.  In. 

Stress  per 
Sq.  In. 

IK 

1.2500 

1.0768 

0.911 

6832 

1  A 

1.3125 

1  .  1393 

1.019 

7642 

IjJ 

1  .  3750 

1.2018 

1.134 

8505 

1  A 

1.4375 

1.2643 

1.255 

9412 

1  ^ 

1  .  5000 

1.3268 

1.382 

10365 

l  iV 

1  .  5625 

1  .  3893 

1.515 

11362 

1X8 

1  .  6250 

1.4518 

1.655 

12412 

419     Table  13  shows  the  allowable  loads  on  net  cross-sectional 
areas  of  round  stays  or  braces. 

TABLE  13.  ALLOWABLE  LOADS  ON  ROUND  BRACES  OR  STAY  RODS  • 


Allowable  Stress,  in  Lb.  per  Sq.  In.,  Net  Cross-sectional 

M'   ' 

Net 

Area 

Diameter 
of  Circular 

Cross-sectional 
Area  of  Stay, 

6000 

8500 

9500 

Stay,  In. 

in  Sq.  In. 

Allowable  Load,  in  Lb.,  on  Net  Cross-sectional  Area 

1             1.0000 

0.7854 

4712 

6676 

7462 

1&        1.0625 

0.8866 

5320 

7536 

8423 

iy8      1.1250 

0.9940 

5964 

8449 

9443 

1  &        1  .  1875 

1  .  1075 

6645 

9414 

10521 

1#         1.2500 

1.2272 

7363 

•  10431 

11658 

1&        1.3125 

1.3530 

8118 

115C1 

12854 

Ifi         1.3750 

1.4849 

8909 

12622 

14107 

1&        1.4375 

1.6230 

9738 

13796 

15419 

1J4         1.5000 

1.7671 

10603 

15020 

16787 

1  A        1  •  5625 

1.9175 

11505 

16298 

18216 

iy8         1.6250 

2.0739 

12443 

17628 

19702 

1  tt        1  •  6875 

2.2365 

13419 

19010 

21247 

1M         1.7500 

2.4053 

14432 

20445 

22852 

1H        1.8125 

2.5802 

15481 

21932 

24512 

114         1.8750 

2.7612 

16567 

23470 

26231 

1H         1-9375 

2.9483 

17690 

25061 

28009 

2            2.0000 

3.1416 

18850 

26704 

29845 

2Yz        2.1250 

3.5466 

21280 

30147 

33693 

2^        2.2500 

3.9761 

23857 

33797 

37773 

2%        2.3750 

4.4301 

26580 

37656 

42086 

2^        2.5000 

4.9087 

29452 

41724 

46632 

2%        2.6250 

5.4119 

32471 

46001 

51413 

2M         2.7500 

5.9396 

35638 

50487 

56426 

2%        2.8750 

6.4918 

38951 

55181 

61673 

3            3.0000 

7.0686 

42412 

60083 

67152 

420     Table  14  gives  the  net  areas  of  segments  of  heads  for  use  in 
computing  .stays. 


106  REPORT  OF  BOILER  CODE  COMMITTEE,  AM.SOC.M.E. 

TABLE  14.    NET  AREAS  OF  SEGMENTS  OF  HEADS 


Height 
from 
Tubes 
to 
Shell, 
In. 

Diameter  of  Boiler,  In. 

24 

30 

36 

42 

48 

54 

60 

66 

72 

78 

84 

90 

96 

Area  to  be  stayed,  Sq.  In. 

8 

JH 

,9o* 
103^ 

11 

lly> 

%* 

\*y* 

14 

%y> 
!8* 

J6H 

8* 

IE* 
%" 
%» 
§* 
1* 

23K 

24 

U* 

»» 

26)4 
27 
27^ 
28 
28)4 
29 
29>£ 
30 
30* 

g* 

32^ 
33 

g* 
»«•• 

35H.  . 

28 
35 
42 
50 
57 
66 
74 
83 
91 

33 
41 
49 
58 
68 
78 
88 
99 
109 
120 
132 
143 
155 
167 
178 

37 
46 
56 
66 
77 
89 
100 
112 
125 
138 
151 
164 
178 
192 
206 
220 
235 
249 
264 

40 
51 
62 
70 
85 
98 
111 
124 
139 
153 
168 
183 
199 
215 
231 
247 
263 
281 
297 
314 
331 
349 
366 
384 
401 

43 
55 

67 
80 
93 

107 
121 
137 
151 
167 
183 
200 
217 
235 
252 
271 
289 
308 
326 
345 
365 
384 
404 
424 
444 
464 
485 
505 
526 

47 
59 
72 
86 
99 
114 
130 
146 
163 
180 
197 
216 
234 
254 
273 
291 
312 
332 
353 
374 
396 
417 
439 
461 
483 
505 
528 
551 
574 
597 
620 
642 
667 
689 
714 
737 
761 

51 
63 
76 
91 
106 
123 
138 
156 
174 
193 
211 
230 
250 
271 
291 
312 
334 
357 
378 
400 
424 
448 
470 
496 
519 
543 
568 
594 
618 
643 
668 
695 
719 
745 
771 
798 
824 
850 
877 
904 
930 

53 
66 
82 
96 
112 
131 
147 
165 
184 
204 
224 
246 
266 
287 
309 
332 
355 
380 
402 
426 
450 
476 
500 
528 
552 
578 
604 
632 
658 
687 
713 
740 
768 
797 
825 
855 
882 
909 
939 
968 
997 
1028 
1056 
1084 
1115 

55 
70 
86 
101 
117 
135 
155 
173 
194 
216 
235 
258 
280 
303 
326 
350 
374 
399 
425 
449 
476 
501 
529 
558 
583 
613 
640 
669 
697 
726 
754 
784 
814 
843 
875 
907 
936 
968 
998 
1030 
1060 
1092 
1123 
1155 
1187 
1218 
1252 
1286 
1317 

58 
74 
90 
105 
123 
142 
161 
181 
203 
224 
247 
270 
294 
318 
343 
368 
394 
420 
447 
471 
500 
526 
555 
584 
613 
643 
673 
703 
734 
765 
796 
827 
859 
892 
922 
956 
987 
1024 
1053 
1089 
1120 
1157 
1187 
1221 
1255 
1290 
1324 
1359 
1394 
1430 
1465 
1500 
1536 

60 
76 
92 
111 
129 
147 
169 
189 
213 
234 
256 
282 
305 
333 
357 
382 
411 
436 
467 
494 
520 
552 
580 
613 
642 
675 
705 
739 
769 
800 
830 
866 
897 
934 
966 
1003 
1035 
1073 
1106 
1145 
1177 
1211 
1248 
1284 
1321 
1358 
1394 
1433 
1467 
1508 
1542 
1578 
1617 
1654 
1692 

63 
80 
95 
116 
132 
153 
174 
196 
219 
243 
267 
293 
319 
345 
372 
400 
423 
457 
486 
516 
543 
577 
604 
641 
667 
706 
733 
766 
•800 
835 
869 
904 
939 
975 
1010 
1047 
1083 
1120 
1157 
1195 
1232 
1270 
1305 
1347 
1382 
1424 
1459 
1496 
1538 
1575 
1617 
1655 
1695 
1735 
1775 
1810 
1857 

65 
82 
98 
119 
137 
160 
183 
204 
230 
252 
279 
302 
331 
360 
386 
417 
443 
475 
502 
536 
564 
598 
631 
663 
699 
729 
766 
797 
835 
867 
906 
945 
978 
1018 
1051 
1092 
1126 
1167 
1202 
1243 
1279 
1321 
1360 
1400 
1442 
1480 
1523 
1561 
1605 
1650 
1687 
1733 
1770 
1816 
1856 
1900 
1941 
1984 
2026 

36 

E?* 

APPENDIX  107 

SAFETY  VALVES 

Method  of  Computing  Table  8.  The  discharge  capacity  of 
a  safety  valve  is  expressed  in  equations  2  and  3  as  the  product  of  0 
and  II.  The  discharge  capacities  are  given  in  Table  8  for  each  valve 
size  at  the  pressures  shown  and  are  calculated  for  various  valve  sizes, 
pressures  and  for  three  different  lifts.  The  discharge  capacities  are 
proportional  to  the  lifts,  so  that  intermediate  values  may  be  obtained 
from  the  Table  by  interpolation. 

C  =  total  weight  or  volume  of  fuel  of  any  kind  burned  per 
hour  at  time  of  maximum  forcing,  Ib.  or  cu.  ft. 

H  =  the  heat  of  combustion,  B.t.u.  per  Ib.  or  cu.  ft.  of  fuel 
used. 

D  —  diameter  of  valve  seat,  in. 

L  =  vertical  lift  of  valve  disc,  in.,  measured  immediately  after 
the  sudden  lift  due  to  the  pop. 

P  —  absolute  boiler  pressure  or  gage  pressure  plus  14.7  Ib.  per 
sq.  in. 

1100  —  the  number  of  B.t.u.  required  to  change  a  pound  of  feed 
water  at  100  deg.  fahr.  into  a  pound  of  steam. 

The  boiler  efficiency  is  assumed  as  75  per  cent. 

The  coefficient  of  discharge,  in  Xapier's  formula,  is  taken  as  96 
per  cent. 

(7x^X0.75    s.uiex^x^xo.Toyx^X0-96  f°r  valve 


1100X3600"  ~~70  45-deg.seat.(l) 

CH=  160,856  XPXDXL  for  valve  with  bevel  seat  at  45  deg.  (2) 

for  valve  with  flat  seat  at  90  deg.  (3) 


METHOD  OF  CHECKING  THE  SAFETY  VALVE  CAPACITY  BY  MEASURING 
THE  MAXIMUM  AMOUNT  OF  FUEL  THAT  CAN  BE  BURNED 

422  The  maximum  weight  of  fuel  that  can  be  burned  is  deter- 
mined by  a  test.  The  weight  of  steam  generated  per  hour  is  found 
from  the  formula: 

w       (7X^X0.75 

-"  where 


108  REPORT  OF  BOILER  CODE  COMMITTEE,  AM.SOC.M.B. 

W  =  weight  of  steam  generated  per  hour,  Ib. 

C  =  total  weight  of  fuel  burned  per  hour  at  time  of  maxi- 
mum forcing,  Ib. 

H  —  the  heat  of  combustion  of  the  fuel,  B.t.u.  per  Ib.    (see 
Par.  427). 

The  sum  of  the  safety  valve  capacities  marked  on  the  valves  as 
provided  for  in  the  Rules  shall  be  equal  to  or  greater  than  the  maxi- 
mum evaporative  capacity  of  the  boiler. 

Table  8  may  be  used  for  determining  the  number  of  safety  valves 
required  as  illustrated  in  the  following  examples : 

423  Example  1 :   A  boiler  at  the  time  of  maximum  forcing  uses 
2150  Ib.  of  Illinois  coal  per  hour  of  12,100  B.t.u.  per  Ib.    Boiler  pres- 
sure, 2,25  Ib.  per  sq.  in.  gage. 

2150X12,100  =  CH  =  26,015,000 

Table  8  shows  that  two  3%-in.  bevel  seated  valves  with  0.11  in. 
lift,  or  one  3-in.  bevel  seated  valve  with  0.10  in.  lift  and  one  3!/2^n. 
bevel  seated  valve  with  0.11  in.  lift,  would  discharge  the  steam'  gen- 
erated. 

424  Example  2:   Wood  shavings  of  heat  of  combustion  of  6400 
B.t.u.  per  Ib.  are  burned  under  a  boiler  at  the  maximum  rate  of  2000 
Ib.  per  hour.     Boiler  pressure,  100  Ib.  per  sq.  in.  gage. 

2000X6400  =  CH=  12,800,000 

Table  8  shows  that  two  Si/^-in.  bevel  seated  valves  with  0.11  in.  lift, 
or  one  3-in.  bevel  seated  valve  with  0.08  in.  lift  and  one  4-in.  bevel 
seated  valve  with  0.12  in.  lift,  would  discharge  the  steam  generated. 

425  Example  3:    An  oil-fired  boiler  at  maximum  forcing  uses 
1000  Ib.  of  crude  oil  (Texas)  per  hour.     Boiler  pressure.  275  Ib.  per 
sq.  in.  gage. 

1000X18,500  =  CH  =  18,500,000 

Table  8  shows  that  two  S^-in.  bevel  seated  valves  with  0.06  in. 
lift,  or  two  3-in.  flat  seated  valves  with  0.05  in.  lift,  or  two  2y2-in^ 
flat  seated  valves  with  0.06  in.  lift,  would  discharge  the  steam  gen- 
erated. 

42.6  Example  4  •'  A  boiler  fired  with  natural  gas  consumes  3000 
cu.  ft.  per  hour.  The  working  pressure  is  150  Ib.  per  sq.  in.  gage. 

3000X960  =  CH  =  2,880,000 


APPENDIX  109 

Table  8  shows  that  two  l^-in.  bevel  seated  valves  with  0.05  in. 
lift,  or  two  1-in.  flat  seated  valves  with  0.01  in.  lift,  would  discharge 
the  steam  generated. 

427  For  the  purpose  of  checking  the  safety  valve  capacity  as 
described  in  Par.  422,  the  following  values'  of  heats  of  combustion 
of  various  fuels  in  B.t.u.  per  Ib.  or  per  cu.  ft.  may  be  used : 

B.  t.  u.  per  Ib. 

Semi-bituminous  coal    '. 14,500 

Anthracite 13,700 

Screenings 12,500 

Coke    ." 13,500 

"Wood,  hard  or  soft,  kiln  dried 7,700 

Wood,  hard  or  soft,  air  dried 6,200 

Wood   shavings    6,400 

Peat,  air  dried,  25  per  cent  moisture 7,500 

Lignite 10,000 

Kerosene    20,000 

Petroleum,  crude  oil,  Penn 20,700 

Petroleum,  crude  oil,  Texas 18,500 

B.  t.  u.  per 
cu.  ft. 

Natural  gas 960 

Blast  furnace  gas 100 

Producer  gas 150 

Water  gas,  uncarburetted 290 


REPORT  OF  BOILER  CODE  COMMITTEE,  AM.SOC.M.E 

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APPENDIX  113 

FUSIBLE  PLUGS 

428  Fusible  plugs,  if  used,  shall  be  filled  with  tin  with  a  melting 
point  between  400  and  500  deg.  fahr. 

429  The  least  diameter  of  fusible  metal  shall  be  not  less  than  1/2 
in.,  except  for  maximum  allowable  working  pressures  of  over  175  Ib. 
per  sq.  in.  or  when  it  is  necessary  to  place  a  fusible  plug  in  a  tube,  in 
which  case  the  least  diameter  of  fusible  metal  shall  be  not  less  than 
%  in- 

4-30     Each  boiler  may  have  one  or  more  fusible  plugs,  located  as 
follows : 

a  In  Horizontal  Eeturn  Tubular  Boilers — in  the  rear  head, 
not  less  than  2  in.  above  the  upper  row  of  tubes,  the  meas- 
urement to  be  taken  from  the  line  of  the  upper  surface  of 
tubes  to  the  center  of  the  plug,  and  projecting  through 
the  sheet  not  less  than  1  in. 

5  In  Horizontal  Flue  Boilers — in  the  rear  head,  on  a  line  with 
the  highest  part  of  the  boiler  exposed  to  the  products  of 
combustion,  and  projecting  through  the  sheet  not  less  than 
1  in. 

c  In  Traction,  Portable  or   Stationary  Boilers  of  the  Loco- 
motive Type  or  Star  Water  Tube  Boilers — in  the  highest 
part  of  the  crown  sheet,  and  projecting  through  the  sheet 
.  not  less  than  1  in. 

d  In  Vertical  Fire-tube  Boilers — in  an  outside  tube,  not  less 
than  one-third  the  length  of  the  tube  above  the  lower  tube 
sheet. 

e  In  Vertical  Fire-tube  Boilers,  'Corliss  Type — in  a  tube,  not 
less  than  one-third  the  length  of  the  tube  above  the  lower 
tube  sheet. 

/  In  Vertical  Submerged  Tube  Boilers — in  the  upper  tube 
sheet,  and  projecting  through  the  sheet  not  less  than  1  in. 

g  In  "Water-tube  Boilers,  Horizontal  Drums,  Babcock  &  Wilcox 
Type — in  the  upper  drum,  not  less  than  6  in.  above  the 
bottom  of  the  drum,  over  the  first  pass  of  the  products 
of  combustion,  and  projecting  through  the  sheet  not  less 
than  1  in. 

h  In  Stirling  Boilers,  Standard  Type — in  the  front  side  .of 
the  middle  drum,  not  less  than  4  in.  above  the  bottom  of 
the  drum,  and  projecting  through  the  sheet  not  less  than 
•lin. 


114  REPORT  OF  BOILER  CODE  COMMITTEE,  AM.SOC.M.E. 

i  Iii  Stirling  Boilers,  Superheater  Type — in  the  front  drum, 
not  less  than  6  in.  above  the  bottom  of  the  drum,  exposed 
to  the  products  of  combustion,  and  projecting  through  the 
sheet  not  less  than  1  in. 

j  In  Water-tube  Boilers,  Heine  Type — in  the  front  course  of 
the  drum,  not  less  than  6  in.  above  the  bottom  of  the  drum, 
and  projecting  through  the  sheet  not  less  than  1  in. 

Tc  In  Ptobb-Mumford  Boilers,  Standard  Type — in  the  bottom 
of  the  steam  and  water  drum,  24  in.  from  the  center  of  the 
rear  neck,  and  projecting  through  the  sheet  not  less  than 
1  in. 

Z  In  Water-tube  Boilers,  Almy  Type — in  a  tube  or  fitting  ex- 
posed to  the  products  of  combustion. 

m  In  Vertical  Boilers,  Climax  or  Hazelton  Type — in  a  tube  or 
center  drum  not  less  than  one-half  the  height  of  the  shell, 
measuring  from  the  lowest  circumferential  seam. 

n  In  Cahall  Vertical  Water-tube  Boilers — in  the  inner  sheet 
of  the  top  drum,  not  less  than  6  in.  above  the  upper  tube 
sheet,  and  projecting  through  the  sheet  not  less  than  1  in. 

o  In  Wickes  Vertical  Water-tube  Boilers — in  the  shell  of  the 
top  drum  and  not  less  than  6  in.  above  the  upper  tube 
sheet,  and  projecting  through  the  sheet  not  less  than  1  in. ; 
so  located  as  to  be  at  the  front  of  the  boiler  and  exposed  to 
the  first  pass  of  the  products  of  combustion. 

p  In  Scotch  Marine  Type  Boilers — in  the  combustion  chamber 
top,  and  projecting  through  the  sheet  not  less  than  1  in. 

q  In  Dry  Back  Scotch  Type  Boilers — in  the  rear  head,  not  less 
than  2  in.  above  the  upper  row  of  tubes,  and  projecting 
through  the  sheet  not  less  than  1  in. 

r  In  Economic  Type  Boilers — in  the  rear  head,  above  the  upper 
row  of  tubes. 

s  In  Cast-Iron  (Sectional  Heating  Boilers — in  a  section  over 
and  in  direct  contact  with  the  products  of  combustion  in 
the  primary  combustion  chamber. 

t  In  Water-tube  Boilers,  Worthington  Type — in  the  front  side 
of  the  steam  and  water  drum,  not  less  than  4  in.  above  the 
bottom  of  the  drum,  and  projecting  through  the  sheet  not 
less  than  1  in. 

u  For  other  types  and  new  designs,  fusible  plugs  shall  be  placed 
at  the  lowest  permissible  water  level,  in  the  direct  path 
of  the  products  of  combustion,  as  near  the  primary  com- 
bustion chamber  as  possible. 


INDEX 

TO 

RULES  FOR  THE 

CONSTRUCTION  OF  STATIONARY  BOILERS 

AND  FOR  ALLOWABLE  WORKING 

PRESSURES 


INDEX  TO  COMPLETE  RULES 117 

INDEX  TO  RULES  TOR  NEW  INSTALLATIONS  OF  POWER  BOILERS.  .  131 

INDEX  TO  RULES  FOR  NEW  INSTALLATIONS  OF  HEATING  BOILERS  141 

INDEX  TO  RULES  FOR  EXISTING  INSTALLATIONS 145 


115 


INDEX  TO  COMPLETE  RULES 


A  PAGE  PAE. 

/  ccess   and  firing  doors,   power  boilers 79  327-328 

/Access  and   firing    doors,    heating   boilers 86  370 

Adamson  furnace    62  242 

Additional  safety  valves,  existing  installations 91  393 

Adjustment  of  safety  valves  for  blow  down 74  281 

Age  limit  for  lap  seam  boilers 89  380 

Allowable  load  on  stay-bolts,    table    of 104  418-419 

loads  on  circular  braces    105  419 

loads   on   stays,    table    of 105  419 

stress  on  stays    52  209 

stress  on  stays  and  stay-bolts 54  220 

working  pressure,    heating  boilers 81  338-340 

working  pressure,    existing   installations    89  378-384 

working  pressure,  existing  installations,   heating  boilers 90  383 

working    pressure,    power   boilers 43  179-180 

Altitude  gages    85  362 

Angles  on  h.r.t.  boiler  heads,   36   in.    or  less  diameter. 56  225-229 

Area,  grate  surface,  table  to  determine  size  of  safety  valves 84  356 

segment,   formula  for    54  217 

segments  of  heads  to  be  stayed 53  214 

segments,    table    of    106 

to  be   stayed  in  heads 53  214-217 

to  be  stayed  in  heads  having  manhole 54  218 

Automatic    shut-off    valves    75  292 

non-return  stop  valves   76  303 

B 

Back  pitch  of  riveted  joints 44  182 

Bars,  steel  for  boiler  parts 7  6 

steel,   specifications  for    19  64—  76 

refined   iron,    specifications   for 37  151-163 

Beading  of    tube  ends ; 64  250 

Blow  down   for  safety  valves 74  281 

Blow-off  cock,   power  boilers    77  309-311 

existing    installations     93  401-403 

heating   boilers    86  364 

piping,   new   installations    76  307-313 

piping,    existing    installations     " 93  401—405 

piping,    heating    boilers    86  364 

pipe    and   fittings    77  311 

B'oiler  builder's  stamps,  location  of 80  333 

builder's  stamps,  not  to  be  covered 80  334 

bushing,   for  feed  pipe   connection 77  315 

plate  steel,   specifications  for 11  23-  39 

to  be  stamped  A.S.M.E.  std 79  332 

wet  bottom,   distance  from  floor  line 79  326 

wet  bottom,  distance  from  floor  line    (heating  boilers) 86  369 

Braced  and   stayed  surfaces 49  199-233 

Braced   and  stayed  surfaces    104  418 

117 


118 


INDEX    TO    COMPLETE    RULES 


PAGifl  PAR. 

Braces,  diameter  of  pins,  area  of  rivets  in  and  design  of  crowfeet  for.  ...  55  223 

made   of  steel  plate 7  5 

made   of   steel   plate    (gussets) 56  224 

spacing  between    51  203 

steel  bars  for 7  6 

when  welded   7  4 

Brackets,  to  support  h.r.t.  boilers 79  325 

Brown   furnaces    63  243-244 

B.t.u.    of   various    fuels 109  427 

Butt  and  double-strap  joint 

double  riveted    97  413 

triple    riveted    98  414 

quadruple    riveted     99  415 

quintuple   riveted    101  416 

Butt  straps,  tables  of  minimum  thicknesses  of 9  19 

straps,  to  be  rolled  or  formed 45  191 

straps,  of  equal  width 103  417 

straps,  saw  tooth    103  417 

0 

Calking     65  257 

Capacity  of  safety  valves 

examples  of  checking    108  423-426 

method   of   checking    107  422-427 

method  of   checking    (existing  installations) 91  391-392 

Cast  iron    (See  gray  iron  castings  or  malleable  castings) 

for  headers    64  246 

used  with  superheated  steam    8  12 

boiler,   hydrostatic   pressure   test   of 87  372 

boiler,   maximum  pressure  allowed  on 87  374 

boiler,   section  to  be  tested    87  372 

headers,  maximum  pressure  allowed  on,  existing  installations 90  382 

headers,  maximum  pressure  allowed  on,  power  boilers 64  245-247 

headers,  tested  to  destruction 64  247 

Cast  steel   (See  steel) 

Castings,  specifications  for  gray  iron • 26  95-110 

specifications  for  malleable  iron 29  111— ICO 

specifications    for    steel    , .    22  77-94 

Channel  irons  for  flat  heads 50  201 

Check  valve   on   feed-pipe    77  317 

Check  valve   on  feed-pipe,  existing  installations 93  406 

Checking  safety  valve  capacity,   method  of 107  422-427 

Checking  safety  valve  capacity,  method  of,   existing  installations 91  391-392 

Circular  furnaces    and   flues 61  239-241 

Circular  manhole  opening    65  258 

Circumferential    joints    44  184-185 

Cleanout  door  in  setting    79  327 

Cock   (See  valves,  gage  cocks,  blow-off  cocks) 

Combined  area  of  safety  valves 74  280 

Combustion  chamber,  materials  to  be  used  in 7  2 

Combustion   chamber,    sling  stays 60  235-236 

Combustion  chamber,   tube  sheets  of. 59  234 

Cones,   truncated,    maximum   allowable   working  pressure   on 58  231 

Connections,    flanged    82  346 

safety    valve     73  277-278 

steam   gages    75  296 

water    column    78  320-321 

Contraction    of   steam   mains,    provision   for 76  305 

Convex  and  concave  heads 49  195 

Corrugated    furnaces    63  243 

Covers,  manhole  and  handhole   .                    7  5 


INDEX    TO    COMPLETE    RULES 


119 


PAGE  PAR. 

Covers,  manhole,   material    67  262 

Cross  boxes,  material  of 8  9 

Cross  pipes  connecting  steam  and  water  drums,   material  of 8  9 

Crown   bars    and   girder    stays 58  230 

Crushing   strength   of   steel   plate 8  15 

Crushing  strength  of  steel  plate,  existing  installations 90  387 

Crushing  strength,    applied  to   joints 95  410 

Curved  surfaces  to  be  stayed 58  230 

D 

Damper  regulator,   connected  to  steam  space 86  365 

Damper  regulator,  connected  to  water  column 75  295 

Damper  regulator,  connected  to  water  column,  existing  installations 92  397 

Diagonal  braces    54  221 

stays,    stresses    in    54  221-222 

tube  holes  in  shell  or  drum 47  193 

Dial  of  steam  gage    75  297 

Diameter   of  fusible   metal  in  fusible  plug 113  429 

Diameter  of   rivet  holes,   old  boilers 90  388 

Direct  spring-loaded,  safety  valve,  construction  of 69  272 

Discharge  capacity  of  safety  valves 68  270-274 

Discharge  pipe  from  safety  valves 73  278-279 

Dished    heads     49  195-198 

Dished    heads,    corner    radius    of 49  197 

Dished  heads,  with  manhole  opening 49  195 

Domes     48  194 

Door,  access  and  firing,  minimum  size  of 79  327—328 

Door,  access  and  firing,  minimum  size  of,  heating  boilers 86  370 

Door,   frame  rings,    material    of 8  13 

Door  latches    79  328 

Doubling    plates    50  199 

Down-draft  boilers,    safety  valves   for 85  359 

Drains  from  stop  valves 76  303-304 

from  stop  valves,    existing  installations 92  400 

from    superheater    76  306 

Drilling   rivet   holes    65  253-254 

Drilling  tube  holes    64  248-249 

Drum  or  shell,  longitudinal  joints  of   (See  joints) 45  187 

Drum,   material  of    < 7  2-     3 

E 

Edge  of  plate  to  center  of  rivet 44  183 

Edges  of  plates  for  calking 65  257 

Edges  of  tube  holes  to  be  removed 64  249 

Efficiency   of   ligament,    between   tube    holes 46  192 

of  ligament,   between  diagonal  tube  holes 47  193 

of  riveted  joints    44  181 

of    riveted   joints,    to    calculate 95-103  410-417 

Elbow  on   escape   pipe,    from   safety   valve 73  279 

Elliptical   manhole,    size    of    65  258 

End  of  feed  pipe,  to  be  open 77  314 

Ends  of  stay-bolts,  to  be  riveted  over ' 50  200 

of  stays  below  tubes 53  216 

of  tubes,    fire-tube   boilers 64  250 

of  tubes,  water-tube  boilers,   and  superheaters 64  251-252 

Equalizer,    to   support  h.r.t.    boilers 78  324 

Escape   pipe,    from   safety  valve 73  278-279 

Escape  pipe,  from  safety  valve,  existing  installations 91  394 

Escape  pipe,  from  safety  valve,  heating  boilers. 83  355 

Examples   of  checking   safety  valve   capacities 108  423-426 

Existing  installations    89-93  378-409 


120 


INDEX    TO    COMPLETE    RULES 


PAGE  TAB. 

Existing    installations,    steam    heating    boilers 90  383 

Expansion   of  steam  mains,   provisions   for 76  305 

Extra  heavy  fittings  on  blow-off 77  310-311 

Extra   thick   tube,    for   fusible   plug 113  429 

F 

Factors  of  safety 

for   domes    when    single    riveted 48  194 

existing  boilers    : 89  379 

new    installations     43  180 

second  hand  boilers    90  381 

steel  heating  boilers    , 81  340 

Feed  pipe,   ends  to  be   open 77  314 

Feed  pipe,  fittings  -and  valves  on v  .  .  .  77  317 

Feed   piping,    power  boilers    77  314—318 

piping,   existing  installations    93  406 

water   discharge    77  315 

water,    discharge    clear    of   joints 77  316 

water  regulator,    connection  to 75  295 

water   supply   apparatus    78  318 

Fire-box  steel,   for  shells,   drums 7  2 

box    steel,    specifications    for 11  23-  39 

brick   casing,    for   blow-off    pipe 77  312 

tube   boiler,    manhole    in 67  264 

tube  boiler,  thicknesses   of  tubes  of 10  22 

Firing  doors    79  327-328 

Fittings   and   appliances,    existing   installations 92  395-407 

Fittings   and    appliances,    heating  boilers 66  364-368 

Fittings  and  appliances,    power  boilers 76  299-322 

Flange  fittings,   tables  of  sizes  of 110-111 

of  manhole  opening    54  218 

Bteel,   for  heating  boilers 81  337 

steel,   for   shells,    drums    7  3 

steel  specifications   for    11  23-  39 

Flanged  connections,    heating  boilers 82  346 

Flanged  construction  for  water  leg  and  door  frame  rings 8  13 

Flanges,   cast  iron,  thickness  of 76  299 

Flanges,   reinforcing,   thickness  and  material  of 68  268 

Flaring  of  tube  ends 64  251 

Flat  surfaces,  to  be  stayed 49  199 

Flat  surfaces,  to  be  stayed  between  tubes  and  between  tubes  and  shell.  ...  53  216 

Flues,   circular,   pressure   allowed  on ' 61  241 

Fox    furnaces     63  243-244 

Fuels,   heats   of   combustion    of 109  427 

Furnace  sheets,   stamps  to  be  visible  on 79  331 

Furnaces : 

Adamson  type 62  242 

Brown    63  243 

circular   flues    61  241 

corrugated      63  243 

Pox 63  243 

internal    cylindrical,    staying    of 52  212 

Leeds    suspension    bulb    63  243 

material   of 7  2 

Morison      63  243 

plain   circular    61  239-240 

Purves    63  243 

thickness  of  corrugated  or  ribbed    64  244 

vertical   boilers    60  237-238 

Fusible    plugs    113  428-430. 

Fusible  plugs,   location  of    .  T ,  ,  , . , ,  „  t ,  ,  .  .  ,  113  430 


INDEX   TO    COMPLETE    RULES 


121 


G                                                                        I'AGM  PAB. 

Gage,   altitude    .  .  i 85  362 

cocks,    existing    installations     92  396 

cocks,    heating   boilers    86  367 

cocks,    power   boilers    75  294 

inspector's,    connection    for 75  298 

steam  and  connections,   existing  installations 92  398 

steam  and  connections,   heating  boilers 85  361 

steam  and  connections,   power  boilers 75  296 

steam,    dial    of    75  297 

water,    glass,   existing   installations 92  395-396 

water,    glass,    heating    boilers 86  366 

water,   glass,   power   boilers 75  291-295 

Gas  fired  boilers,   safety  valves  for 85  360 

Girder  stays  and  crown  bars 58  230 

Globe  valve,  not  to  be  used  on  blow-off, 77  308 

Globe  valve  on  feed   pipe 77  314 

Grate  surface,  table  of,  for  safety  valves 84  358 

Gray   iron   castings,    specifications  for 26  95-110 

Gusset  stays,   stresses   in 54  221-224 

H 

Handhole    covers,    material    • 7  5 

Handholes,  in  h.r.t.  boilers 67  264 

in    locomotive    type    boiler 67  265 

in   vertical   fire   engine   boilers. 67  267 

in  vertical  fire  tube  boilers 67  266 

Headers,  cast  iron,  existing  installations 90  382 

cast  iron,   new  boilers 64  245 

cast  iron,  pressure   allowed  on 64  245—247 

and  pressure  parts,   material  of 8  9 

Heads,   angles  for  staying  upper  segments 56  225-229 

area  of   segments  to  be   stayed 53  213-214 

217 

area  of  segments  to  be  stayed,  table  for 106  420 

convex   end    concave     49  195—198 

segments   of,    area  to   be   stayed 53  213—214 

217 

stamps  to  be  visible 79  331 

stiffeners    for     50  201 

Heating  boilers    81  335-377 

Heating    boilers,    existing    installations 90  383-384 

Heating  boilers,  to  which  the  rules  of  power  boilers  shall  apply 81  335 

Heat   of   combustion    of   various   fuels 109  427 

Holes  for  rivets 65  254 

for  screw  stays    52  210 

for  wash-out,   heating  boilers , 82  345 

for   wash-out,    power   boilers 67  265-267 

Horizontal  return  tubular  boilers: 

location   of   feed-water    discharge 77  315 

longitudinal  joints,  to  be  above  fire  line 45  189 

manhole   below  tubes    67  264 

maximum  length   of    joint 45  190 

method    of   supporting 78  323-324 

staying  heads  of,    36   in  or  less 56  225 

water  column   connections    78  320 

Hot   water   boilers    81  335-377 

Hydrostatic  pressure  test 

of  cast   iron  headers    64  247 

heating   boilers    87  372-374 

old  boilers    93  408-409 

power   boilers    79  329-330 

on  sections  of  cast  iron  boiler ,. . .  87  372 


122 


INDEX    TO    COMPLETE    RULES 


PAB. 

Inspection   at  shop,   heating  boilers 87  375 

Inspector's    test    gage    connection 75  298 

Inspirator  or  injector,  used  to  feed  boiler 78  318 

Insulating  material,  not  to  cover  boiler  stamps 80  334 

Internal  pipe,    in   steam   space 75  290 

Iron,    cast    (See   cast  iron) 

for  stay  bolts,  speciiications  for 34  139-150 

rivets,    specifications    for    31  121-138 

rivets,    shearing   strength   of 8  16 

wrought,    stays   and    stay    bolts 7  7 

wrought,   stays  and  stay  bolts,    specifications 34  139-150 

wrought,   tensile   strength,   existing  installations 90  385 

wrought,  water  leg  and  door  frame  rings 8  13 

J 

Joints,    back  pitch    44  182 

Joints,  butt  and  double  strap,  double  riveted,   example  of 97  413 

butt  and  double  strap,  triple  riveted,  example  of 98  414 

butt  and  double  strap,  quadruple  riveted,  example  of 99  415 

butt  and  double  strap,   quintuple  riveted,  example  of 101  416 

butt  and  double  strap,  required  on  shell  or  drum  over  36  in.  diameter  45  187 

calking  of    65  257 

circumferential     44  184-185 

of  domes    48  198 

efficiency    of     44  181 

efficiency  of,   detailed  methods  of  calculation 95  410 

existing  boilers 89  380 

heating   boilers    82  341-344 

lap,  double  riveted,  longitudinal  or  circumferential,  example  of 96  412 

lap    crack 90  384 

lap  -riveted,  allowed  on  shell  or  drum  not  over  36  in.  diameter 45  188 

lap  riveted,  allowed  on  domes 48  194 

lap  single  riveted,  longitudinal  or  circumferential,  example  of 96  411 

longitudinal    45  187-191 

longitudinal  lap  joints  on  heating  boilers 82  341 

longitudinal,   location  of  rivet  holes  on 44  183 

longitudinal  of  furnace  v.t.  boiler  to  be  staybolted 60  238 

longitudinal  of  h.r.t.  boiler  to  be  above  the  fire  line 45  189 

longitudinal  of  h.r.t.  boiler  to  be  above  the  fire  line,  heating  boilers.  .  86  371 

longitudinal,   maximum  length  of    45  190 

longitudinal,   maximum  length   of,   heating  boilers 82  342 

power   boilers    44  181-191 

protection  of    82  344 

welded    45  186 

L 

Lamphrey  fronts,   valves  on    78  319 

Lamphrey   fronts,    valves   on,    existing   installations 93  407 

Lap  joint   crack    90  384 

Lap  joints: 

length  of,    heating  boilers 82  342 

length  of,  power  boilers 45  190 

longitudinal   or  circumferential,  single  riveted    96  411 

longitudinal  or  circumferential,  double  riveted 96  412 

longitudinal  domes    48  194 

longitudinal   hot   water  boilers 82  343 

longitudinal    lap    crack 90  384 

longitudinal,  steam  heating  boilers 82  341 

Lap  welded  tubes,   specifications  for 40  164-178 

Latches,  door 79  328 


INDEX    TO    COMPLETE    RULES 


123 


PAGB          PAK. 

Laying  out  shell  plates,    furnace   sheets   and  heads 79  331 

Leeds  suspension  bulb  furnaces 63  243 

Length  of  stays  between  supports 54  220 

Ligament  between  tube  holes,   efficiency  of 46  192—193 

Load  allowed  on   stay-bolts 54  220 

Location  of  A.S.M.E.  stamp 80  333 

of   domes    48  194 

of   fusible   plugs    113  430 

Locomotive  type  boiler,   water  leg  and  door  frame  rings 8  13 

Longitudinal    joints     45  187—191 

steam    heating   boilers    82  341 

hot  water  boilers    82  343 

lap    crack     90  384 

on    domes     48  194 

of  h.r.t.  boilers  to  be  above  fire  line,  heating  boilers 86  371 

of  h.r.t.  boilers  to  be  above  fire  line,  power  boilers 45  189 

Low  pressure    steam  boiler 81  335-377 

Lugs,   made  of  steel  plate 7          5 

Lugs,  to  support  h.r.t.  boilers 78  323-325 

M 

Main  steam  pipe,  stop  valve  on 76  301-304 

Malleable   castings,    specifications   for 29  111-120 

Manholes     65  258-264 

below  tubes,  h.r.t.  boiler 67  264 

below  tubes,   h.r.t.  boiler,   staying  of 54  218 

covers,    material    of    67  262 

covers,    when    plate  steel 7          5 

in  a  dished  head    49  198 

frame,    riveting   of    65  260 

frame,    proportions   of    66  261 

gaskets,  bearing  surface  of 67  263 

in  any  fire  tube  boiler,  over  40  in.  diameter 67  264 

in  dome  heads    67  264 

openings,    minimum  sizes  of 65  258 

plates,    material    of     67  262 

reinforcement,    material    of    65  259 

reinforcement,  on  boiler  48  in.  diameter  or  over 65  260 

Manufacture    (See  specifications) 

Manufacturer's   name,    heating  boilers 87  377 

Manufacturer's   stamp 79  332 

Manufacturer's  stamp  not   to  be   covered 80  334 

Materials,    selection   of    7          1—13 

Materials,    selection  of,    for  heating  boilers 81  335—337 

Maximum   allowable  working  pressure 

braced  and  stayed  surfaces 49  199 

existing  boilers    89  378-384 

heating   boilers    81  338-340 

shells    of   power   boilers 43  179-180 

Methods   of   support    78  323-325 

Morison   furnaces    63  243-244 

Mud   drums,    maximum   allowable   working  pressure 90  382 

Mud  drums,    material   of 8        10 

Muffler  on  safety  valves 73  279 

N 

Name,  manufacturer?,   on  heating  boilers 87  377 

Non-return    stop    valves,    automatic 76  303 

Nozzles,   material  of    8        12 

Nozzles,    and    fittings    76  299 

Number   of    gage    cocks 75  294 

Numbers,    serial    . 79  332 


124  INDEX    TO    COMPLETE    RULES 

PAGE  PAR. 

OG  flanged   construction 8  13 

Oil-fired   boilers,    safety   valves   for 85  360 

Openings,    flanged    connections,    heating   boilers 82  346 

Openings,   threaded  to  be  reinforced 68  268 

Outside  screw  and  yoke  valves,    on  steam  pipe 76  301 

Outside  screw  and  yoke  valves,   on  water  column 75  293 

P 

Pins  in' braces,  diameter  of 55  223 

Pipes,  bottom  blow-off  and  fittings,  existing  instuiiatij;..j 93  401-405 

bottom  blow-off  and  fittings,   heating  boilers 86  364 

bottom  blow-off  and  fittings,   power  boilers 77  3C8 

feed    and    fittings 77  314-317 

in,  steam  space    75  290 

main,  steam,  valves  on 76  301 

or  nipple,    number  of  threads  into  fitting 76  300 

or  nipple,  number  of  threads  into  fitting,  taLb 68  268 

surface  blow-off  and  fittings 76  307 

threads,  minimum  number  of    68  268 

w~ter  column,   and  fittings 78  320 

Piping,    feed    , 77  314-318 

Pitch  of  rivets    • 44  182 

of    rivets     95  410 

of    stay-bolts    .  .  .  .• 50  199 

of  stay-bolts,    table    51  203 

of    stay  tubes 59  233 

Planing  edges  of  plates 65  257 

Plate,    steel,    specifications    for 11  23-  39 

Plates,  thickness,   in  shell  or  dome  after  flanging 9  18 

minimum  thickness   of   in   a  boiler ~ 9  17-  20 

minimum  thickness  of  stayed  flat  surface 49  199 

Plugs,    fusible 113  428-430 

Power  boilers    7-80  1-334 

Power  boiler  requirements  for  certain  heating  boilers 81  335 

Pressure,    allowed  on   cast  iron  boilers 81  338 

allowed  on  shell  or  drum,   formula  for  existing  installations 89  378 

allowed  on  shell  or  drum,   formula  for,  power  boilers 43  180 

maximum  allowable  working,  on  flat  surfaces,  power  boilers 49  199 

maximum  allowable  working,   old  boilers 89  378-384 

maximum  allowable  working,   old  boilers  steam  heating 90  383 

maximum  allowable  working,   heating  boilers 81  338-340 

maximum  allowable  working,   on  shells,  power  boilers 43  179-180 

parts  over  2  in.,  material  of 8  9 

parts  of  superheaters,   material  of , 8  11 

Protection    of    joints     82  344 

Pump,  to  supply  feed  water 78  318 

Purves  furnaces    63  243 

E 

Regulators,    damper    86  365 

Reinforced  threaded  openings  in  shell,  heads  of  drums 68  268 

Relief  valves   for  hot  water  boilers 83  349-350 

Reservoirs,    on   steam   mains 76  305 

Rings,  waterleg  and  door  frame,  material  of 8  13 

Rivet  holes,   finish   and  removal  of  burrs 65  253-254 

iron,   specifications  for    31  121-138 

steel,  specifications  for 15  40-  62 

Riveted  joints    (See  joints) 

Riveting     65  253-256 


INDEX    TO    COMPLETE    RULES 


125 


Rivets  PAQB  PAR. 

allowable   shearing  strength   of 8  10 

allowable    shearing   strength   of,    existing   installations 90  386 

existing  boilers,    diameter  of 90  388 

in  braces,   area   of 55  223 

in  shear   on  lugs  or  brackets 79  325 

in    shear   on    manhole   frames ; 65  260 

length  of  and  heads  for. 65  255 

machine  driven 65  256 

material    of    8  8 

to  completely  fill  rivet  holes 65  255 

Rolling,   ends  of  shell  plates 45  191 

Safety,   factor  of 

for    existing  boilers    89  379 

for  existing  lap   joint  boilers 89  380 

for  power  boilers    43  180 

for   steel  heating  boilers 81  340 

Safety   valves 

additional   on    existing   installations 91  393 

blow-down   adjustment    74  281 

capacity,   method   of  checking 107  422-427 

connections,    existing  boilers    91  394 

connections,    heating   boilers    83  347 

connections,  power  boilers    73—74  276-278 

280 
289-290 

construction    74  282-287 

construction,    heating   boilers    84  356-358 

discharge    capacity,    existing  boilers ,. 91  391-392 

discharge    capacity,    power   boilers 68  270-274 

discharge    capacity,    table    of 70—72 

escape   pipe    for    73  278 

escape  pipe   for,   existing  installations 91  394 

escape  pipe  for,  heating  boilers 83  355 

for   down    draft   boilers 85  359 

for  existing   installations    91  389-394 

for  heating  boilers 83  347-360 

for  oil  and  gas  fired  boilers .  85  360 

formula  for    107  421 

formula  for  heating  boilers 83-84  351-358 

method    of    computing    and    checking 107  421-427 

method  of  computing  and  checking,   ex:sting  installations 91  391-392 

muffler  on ; 73  279 

muffler    on,    existing   installations 91  394 

power   boilers 68  269-290 

required  on  boiler    68  269 

required  on  boiler,   existing  installations 91  390 

required    on   heating   boilers 83  348 

seats  of    69  272 

seats  of  heating  boilers 84  357 

setting  of 68  271-281 

setting  of,    existirr*  inst",lbtiors 91  390 

setting  of,   existing  installations,  heating  betters 83  348 

size   limits,    heating  boilers 83  351 

size   limits,    power    boilers 69  272 

stamping  of 69  273 

stamping  of,   heating  boilers 84  357 

superheater     74  288-289 

table   of,   for  heating  boilers 84  356 

test   of ' 73  275 

testing   of   existing    installations 91  39^ 


126 


INDEX    TO    COMPLETE    RULES 


PAGE  PAR. 

Saw-tooth,  type  of  butt  and  double  strap  joint 103  417 

Screwed  stays,   supporting  of 54  219 

Seamless    tubes,    specifications    for 40  164—178 

Seats  of  safety   valves    69  272 

Second   hand   boilers    90  381 

Sections  of  cast  iron,  to  be  tested 87  372 

Segment,    area  to  be   stayed 53  214-217 

of  head,    to   be   stayed 53  213 

method  of  determining  net  areas,  water  tube  boilers 53  215 

Segments,   table   of    106  420 

Selection  of   material    7  1-13 

Serial  number    79  332 

Setting    of    safety    valves 68  271 

of  safety  valves,   existing  installations 91  390 

of  safety  valves,  existing  installations,  heating  boilers 83  348 

Setting,   method  of,    wet  bottom  heating  boilers 86  369 

Setting,   method  of,    wet  bottom  power  boilers 79  326 

Settings,    heating   boilers    • 86  369-371 

Settings,   power    boilers    78  323-328 

Shearing  strength  of  rivets 8  16 

Shearing  strength  of  rivets,   existing   installations 90  386 

Shell  or   drum,    longitudinal  joints   of 45  187-190 

or  drum,  to  determine  alowable  pressure  on,  new  boilers 43  180 

or  drum,  to  determine  allowable  pressure  on,  existing  boilers 89  378 

plate,    thickness  of    9  17-  20 

Shut-off  valves  on  water  column  pipes 75  293 

Shop  inspection  of  heating  boilers 87  375 

Sizes  of  flanged  fittings,  tables 110-111 

Sling    stays    60  235-236 

Specifications    for    gray    iron    castings 26  95-110 

lap  welded  and  seamless  boiler  tubes 40  164-178 

material,   heating  boilers    81  336 

malleable  castings    29  111-120 

plate   steel    11  23-  39 

refined  wrought  iron  bars 37  151—153 

rivet    iron    31  121-138 

rivet   steel 15  40-  62 

stay  bolt  iron 34  139-150 

stay  bolt  steel   19  63 

steel  bars    19  64-  76 

steel  castings    22  77-94 

Stamping  boilers  A.S.M.E.  std 79  332 

Stamps,  A.S.M.E.  std.,  location  of 80  333 

Stamps,  not  to  be  covered  by  insulation 80  334 

Stamps,  to  be  visible  on  shell  plates,  furnaces  sheets  and  heads 79  331 

Stay  bolted  surface,  to  compute  allowable  pressure  on 49  199 

Stay  bolts 

adjacent  to  edges  of  stay-bolted  surface 51  205 

•adjacent  to  furnace  door  or  other  opening 52  206 

adjacent  to  furnace  joint,  v.t.  boiler 60  238 

diameter    of,    how    measured 52  208 

ends    of    50  200-202 

211 

holes   for    52  210 

iron,  specifications  for    34  139-150 

material   of 7  7 

maximum  allowable  stress  on 54  220 

pitch  of    49  199-204 

steel,    specifications    for .  19  63 

tables   of  allowable   load  on 104  418-419 

Stayed  ar.d  braced   surfaces    49  199-233 

Stayed    flat    surface     49  199 


INDEX    TO    COMPLETE    RULES 


127 


PAGE          PAR. 

Staying  heads    55  222 

heads  h.r.t.  boiler  36  in.  or  less  diameter 56  225-229 

dished  heads    49  196 

furnaces     52  212 

segments   of  heads    53  213 

segments  of  heads  with  manhole  opening 54  218 

Stay-rods,   ends  riveted  over,   to  be  supported 54  219 

Stay-tubes 58  232-233 

Stays,  crown  bars  and  girders 58  230 

cross  sectional  area  in  calculating 52  209 

diagonal   and   gusset,    stresses    in 54  221—222 

224 

maximum    allowable    stress    54  220 

sling    60  235-236 

tables  of  allowable  load   on 104  418-419 

screwed,    supporting   of    54  219 

upset  for  threading    52  211 

end  stay-bolts,allowable  stress  on 54  220 

and  stay-bolts,  table  of  allowable  stress  011 .  .  .  104  418-419 

Steam  gage  and  connections,   existing  installations 92  398 

gage  and  connections,   heating  boilers. 85  361 

gage  and  connections,  power  boilers 75  296—298 

heating  boilers,   existing  installations 90  383—384 

mains    76  305 

mains,   reservoirs   on    76  305 

outlets     76  301 

outlets,   existing  installations    92  399 

Steel  bars,   for  boiler  parts 7          6 

castings,    specifications  for    22        77-  94 

crushing    strength   of   plate 8        15 

for  rivets,    specifications   for 15        40-  62 

for  stay-bolts,    specifications   for 19        63 

plates  exposed  to  fire    7          2 

plates  when  firebox  quality  not   specified 7          3 

plates,    shearing   strength   of 8        16 

stays  and  stay-bolts    49  199—212 

tensile    strength    of,    existing   installations 90  385 

wrought  or  cast,  for  boiler  and  superheater  parts 8        11 

plate,    crushing  strength  of 8        15 

plate,   heating  boilers    81  335-340 

plate,    specifications   for    11        23-  39 

plate,  tensile  strength  of    8        14 

Stop    valves    (See    valves) 

Straps,    butt,    of    equal   width 103  417 

Straps,    butt,    saw-tooth    103  417 

Superheater  drains    76  306 

safety  valve  on    . 74  288-289 

tubes  and  nipples    64  251-252 

Superheaters   and  mountings,    material    for 8        11-  12 

Support,    methods   of,    for  boilers .  78  323-326 

Support   of  stays,    ends   riveted  over 54  219 

Surface   blow-off    76  307 

Suspended  type  of  setting  h.r.t.  boilers 78  324 

T 

Table  of  angles  for  staying  heads 56  225 

constants   for  pitch   of    stay   tubes 59  233 

discharge  capacities  of  spring-loaded  safety  valves ,  . .  . .  69-70 

71-72 

flange    fittings,    standard    110 

flange   fittings,   extra  heavy    Ill 


128 


INDEX    TO    COMPLETE    RULES 


Table  of  muximuftx  allowable  pitch  of  stay-bolts,   ends  riveted 

maximum   allowable   stresses   for   stays   and   stay-bolts .  .  . 

minimum  pipe  threads  for   boiler  connections 

net   areas   of   segments 

round  braces  or  stay  rods  allowable  loads 

sizes  of  safety  valves,   heating  boilers 

sizes    of    rivets,    existing    boilers .  .  .  .  > 

stay-bolts,  allowable  loads,   12  threads  per  inch 

stay-bolts,   allowable  loads,    10  threads  per  inch 

thickness  of  butt  straps 

Tensile  strength  of  steel  or  wrought  iron,  existing  installations 

Tensile  strength  of  steel  plate 

Test,  hydrostatic,  of  existing  installations 

hydrostatic,    of   heating   boilers 

hydrostatic,    of    power   boilers 

of  safety  valve,  existing  installations 

•of  safety  valve,   power  boilers 

of  steam  gage    

gage,  connection  for  

Thermometers  on  hot  water  boilers 

Thickness  of  corrugated  or  ribbed  furnaca 

required   for  boiler  plates 

required  for  butt   straps    

required  for  dome  plates  after  flanging 

required   for   shell  plates 

required  for  tube   sheets 

required  for  tubes  

Threaded  openings  

Threads,  pipe  or  nipple  into  fitting 

Threads,  table  

Tin,  for  fusible  plugs 

Truncated  cones,  maximum  allowable  working  pressure  on 

Tube  ends,  fire  tube  boiler 

ends,   wafer  tube  boilers  and  superheaters 

for  fusible   plug    

heads,  upper,   staying  segments  of  by  steel  angles 

heads,    of   water   tube   boilers 

holes  and  ends    

holes,  diagonal,  in  shell  *>r  drum 

holes  in  shell  or   drum 

holes,    sharp  edges  to   be  removed 

sheets  of  combustion  chambers 

sheets,  minimum  thickness  of. 

sheets,  space  allowed  unstaved  between  tubes  and  between  tubes  and  shell 
Tubes  for  fir.e-tube  boilers,  thicknesses  of 

for  water- tube  boilers,   thicknesses  of 

lapwelded   and  seamless,   specifications   for 

required    thickness .* 

stay     


Valves,   automatic,   on  water  glass 75 

automatic  non-return  stop 

extra  heavy,   on  bottom  blow-off 77 

extra  heavy,   on  main  steam  pipe 

globe,  not  to  be  used  on  blow-off 

globe,    on    feed   pipe 

on  bottom  blow-off    

on  bottom  blow-off,  existing  installations 

on   every  steam  outlet 

on  feed  pipe 77 

on  feed  pipe,  existing  installations 


I'AUH 

PAR. 

51 

204 

54 

220 

68 

268 

106 

420 

105 

419 

84 

358 

90 

388 

1C4 

418 

105 

418 

9 

19 

90 

385 

8 

14 

93 

408-409 

8? 

372-375 

79 

329-330 

91 

391 

73 

275 

75 

298 

75 

298 

86 

363 

64 

244 

9 

17 

9 

19 

9 

18 

9 

18 

9 

20 

10 

21-  22 

68 

268 

76 

300 

68 

268 

113 

428 

58 

231 

64 

250 

64 

252 

113 

429 

56 

225-229 

53 

215 

64 

248-252 

47 

193 

46 

192 

64 

249 

59 

234 

9 

20 

53 

216 

10 

22 

10 

21 

40 

164-178 

10 

21-  22 

58 

232-233 

75 

292 

76 

303 

77 

311 

76 

302 

77 

308 

77 

314 

77 

308-311 

93 

401-403 

76 

301 

77 

317 

93 

406 

INDEX    TO    COMPLETE    RULES 


129 


PAK. 

Valves,   on  Lamphrey  fronts 78  319 

on  Lamphrey  fronts,   existing   installations 93  407 

outside  screw  and  yoke  type,  on  steam  pipes 76  301 

ontside  screw  and  yoke  type,  on  water  column 75  293 

safety   [See  safety  valves) 

stop     76  301-304 

stop,    drains   for    76  303—304 

stop,   existing  installations    92  399 

stop,    existing   installations,    drains 92  400 

Vertical  boilers,   furnaces  of 60  237-238 

fire-tube  boiler,  manhole  in 67  264 

fire-tube  boiler,   waterleg  and  door  frame  ring 8        13 

W 

Washout  holes,  hot  water  boilers 82  345 

Washout  holes,   power  boilers 6?  265-267 

Water  column  and  connections,  existing  installations 92  397 

column  end  connections,  heating  boilers 86  368 

column  and  connections,  power  boilers 75  295 

column  and  connections,   power  boilers 78  320-322 

glass  and  gage  cocks,  location  of,   power  boilers 75  291-292 

glass,   automatic  valves  not  allowed 75  292 

glasses,    existing   installations    92  395 

glasses,    heating  boilers    86  366 

relief  valves  for  hot  water  boilers 83  349— 350 

Waterleg  rings,    material   of    8        13 

Water   tube   boilers 

cast  iron  for  headers  of 64  246 

flaring  of  tube  ends 64  251 

thicknesses  of  tubes  of 10        21 

wrought  or  cast  steel  parts  of 8          9 

Welded  joints    45  186 

Welded    stays     52  209 

Y.*et  bottom  boilers,  height  from  floor  line' 79  326 

Wet  bottom  boilers,  height  from  floor  line,  heating  boilers 86  369 

Working  pressure,    maximum  allowable 

existing    installations     89  378-384 

power    boilers    43  179-18O 

steam  and  hot  water  boilers 81  338-340 

Wrought   iron    (See   iron)  ^ 

Wrought  steel  (See  steel) 


INDEX  TO  RULES  FOR  NEW  INSTALLA- 
TIONS OF  POWER  BOILERS 


PAGE          PAB. 

Access  and  firing  doors,  power  boilers 79  327-328 

Adamson  furnace    62  242 

Adjustment  of  safety  valves  for  blow  down 74  281 

Allowable  load  on  stay-bolts,  table  of 104  418-419 

loads  on  circular  braces    105  419 

loads   on   stays,   table   of 105  419 

stress  on  stays    52  209 

stress   on  stays   and  stay-bolts 54  220 

working  pressure,    power    boilers 43  179—180 

Angles  on  h.r.t.  boiler  heads,   36  in.  or  less  diameter 56  225-229 

Area  of  segment,  formula  for 54  217 

segments  of  heads  to  be  stayed 53  214 

segments,  table  of 106 

to  be  stayed  in  heads 53  214-217 

to  be  stayed  in  heads  having  manhole 54  218 

Automatic    shut-off   valves    75  292 

non-return  stop  valves 76  303 

B 

Back  pitch  of  riveted  joints 44  182 

Bars,   steel  for  boiler   parts 7          6 

steel,   specifications  for    19        64-  76 

refined  iron,    specifications  for    37  151-163 

Beading  of  tube  ends 64  250 

Blow  down  for  safety  valves 74  281 

Blow-off    cock    77  309-311 

piping   new   installations 76  307-313 

pipe    and   fittings    77  311 

Boiler,  builder's  stamps,  location  of 80  333 

builder's  stamps,   not  to  be  covered 80  334 

bushing,    for    feed    pipe    connection .  77  315 

plate  steel,  specifications  for 11        23-  39 

to  be  stamped  A.  S.  M.  E.  std 79  332 

wet  bottom,   distance  from  floor  line 79  326 

Braced  and  stayed  surfaces 49  199-233 

Braced  and  stayed  surfaces 104  418 

Braces,  diameter  of  pins,  area  of  rivets  in  and  d*esign  of  crowfeet  for.  ...  55  223 

made   of   steel   plate 7          5 

made  of  steel  plate,   gussets 56  224 

spacing  between 51  203 

steel  bars  for    7          6 

when  welded 7          4 

Brackets,   to  support  h.r.t.  boilers 79  325 

Brown   furnaces    63  243-244 

B.t.u.    of    various    fuels 109  427 

Butt  and  double-strap  joint,  double  riveted 97  413 

and   double-strap   joint,   triple  riveted 98  414 

and   double-strap  joint,   quadruple  riveted 99  415 

131  l 


132 


INDEX,    NEW    INSTALLATIONS    OF    POWER    BOILERS 


PAGE  PAR. 

Butt   and   double-strap   joint,    quintuple  riveted 101  416 

straps,   tables  of  minimum  thicknesses  of 9  19 

straps,  to  be  rolled  or  formed 45  191 

straps   of   equal  width 103  417 

straps,   saw  tooth    103  417 

0 

Calking 65  257 

Capacity  of  safety  valves,  examples  of   checking 108  423-426 

Capacity  of  safety  valves,    method   of   checking 107  422-427 

Cast  iron    (See  gray  iron  castings  or  malleable  castings) 

for  headers    64  246 

used  with  superheated  steam 8  12 

headers,  maximum  pressure  allowed  on,   power  boilers 64  245-247 

headers,   tested  to  destruction 64  247 

Cast    steel    (See    steel) 

Castings,    specifications   for   gray   iron t 26  95-110 

specifications  for  malleable   iron 29  111-120 

specifications   for  steel    22  77-  94 

Channel   irons   for  flat  heads 50  201 

Check  valve  on  feed-pipe 77  317 

Checking  safety  valve  capacity,   method  of 107  422-427 

Circular   furnaces   and  flues 61  239-241 

Circular  manhole   opening    65  258 

Circumferential   joints    44  184-185 

Cleanout    door    in    setting 79  327 

Cock    (See  valves,   gage  cocks,    blowoff   cocks) 

Combined  area  of  safety  valves 74  280 

Combustion  chamber,   material  to  be  used  in 7  2 

Combustion   chamber,   sling   stays 60  235-236 

Combustion  chamber,   tube  sheets  of 59  234 

Cones,  truncated,  maximum  allowable  working  pressure  on 58  231 

Connections,    safety   valve    , 73  277-278 

steam  gages 75  296 

water   column    78  320-321 

Contraction  of  steam  mains,   provisions  for 76  305 

Convex  and  concave  heads 49  195 

Corrugated  furnaces 63  243 

Covers,    manhole    and   handhole 7  5 

Covers,    manhole,    material     67  262 

Cross  boxes,   material  of -. 8  9 

Cross  pipes  connecting  steam  and  water  drums,  material  of 8  9 

Crown  bars  and  girder  stays   58  230 

Crushing   strength   of   steel   plate 8  15 

Crushing  strength  applied  to  joints 95  410 

Curved   surfaces   to   be   stayed 58  230 

D 

Damper  regulator,  connected  to  water  column 75  295 

Diagonal  braces    54  221 

stays,    stresses   in    54  221-222 

tube  holes  in  shell  or  drum 47  193 

Dial  of   steam  gage 75  297 

Diameter   of  fusible  metal  in  fusible   plug 113  429 

Direct   spring-loaded    safety   valve,    construction   of 69  272 

Discharge    capacity   of    safety   valves 68  270-274 

Discharge  pipe  from  safety  valves 73  278-279 

Dished  heads 49  195-198 

Dished  heads,   corner  radius  of 49  197 

Dished  heads  with  manhole  opening 49  195 

Domes    .  48  194 


INDEX,    NEW   INSTALLATIONS    OF    POWER   BOILERS 


133 


PAGB  PAE. 

Door,   access  and  firing,   minimum  size  of 79  327-328 

Door,   frame  rings,   material  of 8  13 

Door  latches    79  328 

Doubling    plates    50  199 

Drains  from  stop  valves 76  303-304 

Drains  from  superheater 76  306 

Drilling   rivet   holes    65  253-254 

Drilling  tube  holes    64  248-249 

Drum  or  shell,  longitudinal  joints  of   (See  joints) 45  187 

Drum,   material  of    7  2-     3 

E 

Edge  of  plate  to  center  of  rivet,  distance  from 44  183 

Edges  of   plates  for   calking 65  257 

Edges  of  tube  holes  to  be  removed 64  249 

Efficiency  of  ligament,   between  tube  holes 46  192 

of  ligament,  between  diagonal  tube  holes 47  193 

of    riveted    joints    44  181 

of  riveted  joints,   to   calculate 95-103  410-417 

Elbow  on  escape  pipe,   from  safety  valve 73  279 

Elliptical    manhole,    size    of 65  258 

End  of  feed  pipe,  to  be  open . 77  314 

Ends  of  stay-bolts,  to  be  riveted  over 50  200 

stays   below   tubes    53  216 

tubes,   fire-tube  boilers    64  250 

tubes,    water-tube   boilers,    and   superheaters 64  251—252 

Equalizer,    to   support  h.r.t.   boilers 78  324 

Escape   pipe,    from   safety  valve 73  278-279 

Examples  of  checking  safety  valve  capacities 108  423-426 

Expansion  of  steam  mains,   provisions  for 76  305 

Extra   heavy   fittings   on    blow-off 77  310-311 

Extra   thick   tube,    for   fusible    plug 113  429 

F 

Factors  of  safety  for  domes  when  single  riveted. 48  194 

Factors  of  safety  for  new  installations , 43  180 

Feed  pipe,   ends  to  be   open 77  314 

pipe,   fittings   and  valves  on 77  317 

piping,   power  boilers    77  314—318 

water,  discharge    77  315 

water,   discharge  clear  of  joints 77  316 

water,    regulator,    connection   to 75  295 

water,    supply  apparatus 73  318 

Fire-box  steel,  for  shells,  drums 7  2 

-box   steel,    specifications   for 11  23—  39 

brick  casing,  for  blow-off  pipe 77  312 

tube  boiler,   manhole  in 67  264 

tube  boiler,   thicknesses  of  tubes  of 10  22 

Firing   doors    • 79  327-328 

Fittings   and    appliances,    power  boilers 76  299-322 

Flange  fittings,   tables  of  sizes  of 110-111 

of  manhole  opening    54  218 

steel  for  shells,   drums 7  3 

steel   specifications   for 11  23-  39 

Flanged  construction  for  water  leg  and  door  frame  rings 8  13 

Flanges,   cast  iron,   thickness  of 76  299 

Flanges,  reinforcing,   thickness  and  material  of 68  268 

Flaring  of  tube  ends 64  251 

Flat  surfaces,  to  be  stayed 49  199 

Flat  surfaces,  to  be  stayed  between  tubes  and  between  tubes  and  shell ....  53  216 

Flues,   circular,   pressure   allowed   on 61  241 

Fox    furnaces     63  243-244 


134 


INDEX,    NEW    INSTALLATIONS    OP    POWER    BOILERS 


PAGE          PAJB. 

Fuels,   heats   of  combustion   of 109     427 

Furnace  sheets,   stamps  to  be  visible  on 79      331 

Furnaces 

Adamson  type   62     242 

Brown 63      243 

circular    flues    61     241 

corrugated      .  . .  .  t 63      243 

Fox     63      243 

internal    cylindrical,    staying    of 52      212 

Leeds  suspension  bulb    63      243 

material   of    7          2 

Morison    63      243 

plain   circular    -. 61      239-240 

Purves    63      243 

thickness  of  corrugated  or  ribbed 64      244 

vertical   boilers 60      237-238 

Fusible    plugs 113      428-430 

Fusible  plugs,   location  of 113  430 

G 

Gage  cocks,  power  boilers 75  294 

inspector's,    connection   for    75  298 

steam   and  connections,   power  boilers 75  296 

steam  dial   of    75  297 

water,    glass     75      291-295 

Girder  stays  and  crown  bars 58  230 

Globe  valve,   not  to  be  used  on  blow-off 77  308 

Globe  valve,   on  feed  pipe 77  314 

Gray  iron   castings,    specifications   for 26        95—110 

Gusset  stays,   stresses  in 54  221-224 

H 

Handhole   covers,    material    7          5 

Handholes,    in    h.r.t.    boilers 67  264 

in  locomotive   type  boilers 67  265 

in  vertical  fire  engine  boilers 67  267 

in  vertical  fire  tube  boilers 67  266 

Headers,   cast  iron,   new  boilers 64  245 

cast  iron,   pressure  allowed  on 64  245-247 

and  pressure  parts,   material  of 8          9 

Heads,   angles  of  staying  upper  segments 56  225-229 

area  of  segments  to  be  stayed 53  213-214 

217 

area  of  segments  to  be  stayed,  table  for 106  420 

convex    and    concave    49  195-198 

segments  of,  area  to  be  stayed 53  213-214 

217 

stamps   to   be   visible 79  331 

stiffeners  for    50  201 

Heat  of  combustion  of  various  fuels 109  427 

Holes  ?or  rivets    65  254 

screw  stays    52  210 

washout,  power  boilers   67  265-267 

Horizontal  return  tubular  boilers 

location    of   feed-water   discharge 77  315 

longitudinal  joints,  to  be  above  fire  line 45  189 

manhole  below  tubes    67  264 

maximum  length   of  joint 45  190 

method  of  supporting 78  323-324 

staying  heads  of,   36  in.  or  less 56  225 

water  column  connections    ...  78  320 


INDEX,    NEW    INSTALLATIONS    OF   POWER   BOILBKK 


135 


Hydrostatic   pressure   test                                                                                                 PAQB  TAX. 

of   cast    iron   headers 64  247 

power  boilers 79  329-330 

I 

Inspector's  test  gage  connection 75  298 

Inspirator  or  injector,    used  to  feed  boiler 78  318 

Insulating  material,  not  to  cover  boiler  stamps 80  334 

Internal  pipe,    in   steam   space 75  290 

Iron,   cast    (See  cast  iron) 

for    stay   bolts,    specifications    for 34  139—150 

rivets,   specifications  for    .  .  ; .  31  121-138 

rivets,    shearing   strength   of 8  16 

wrought,  stays  and  stay  bolts 7  7 

wrought,    stays   and  stay  bolts,    specifications 34  139-15O 

wrought,   waterleg  and  door  frame  rings 8  13 

J 

Joints,   back   pitch    k .  . . .  44  182  - 

butt  and  double  strap,  double  riveted,  example  of .  . 97  413 

butt  and  double  strap,  triple    riveted,  example  of 98  414 

butt  and  double  strap,  quadruple  riveted,  example  of 99  415 

butt  and  double  strap,   quintuple  riveted,   example  of 101  416 

Joints,  butt  and  double  strap,  required  on  shell  or  drum  over  36  in.  diameter  45  187 

calking   of    65  257 

circumferential     44  184-185 

of  domes    48  198 

efficiency  of    44  181 

efficiency  of  detailed  methods  of  calculation 95  410 

lap,   double  riveted,   longitudinal  or  circumferential,    example   of 96  412 

lap  riveted,  allowed  on  shell  or  drum  not  over  36  in.  diameter 45  188 

lap  riveted,    allowed  on   domes 48  194 

lap,  single  riveted,  longitudinal  or  circumferential,   example  of 96  411 

longitudinal    45  187-191 

longitudinal,  location  of  rivet  holes  on 44  183 

longitudinal,  of  furnace,  v.t.  boiler  to  be  stay-bolted 60  238 

longitudinal,  of  h.r.t.  boiler  to  be  above  the  fire  line 45  189 

longitudinal,    maximum   length   of 45  190 

power  boilers 44  181-191 

welded 45  186 

L 

Lamphrey  fronts,   valves  on 78  319 

Lap  joints,  length  of,  power  boilers 45  190 

joints,   longitudinal   or   circumferential,    double   riveted 96  412 

joints,    longitudinal  or  circumferential,   single  riveted 96  411 

joints,   longitudinal  domes    48  194 

welded   tubes,    specifications   for 40  164—178 

Latches,    door    79  328 

Laying  out  shell  plates,   furnace  sheets   and  heads 79  331 

Leeds  suspension  bulb  furnaces 63  243 

Length  of  stays  between  supports 54  220 

Ligament  between  tube,  holes,   efficiency  of 46  192-193 

Load  allowed  on  stay-bolts 54  220 

Location  of  A.   S.   M.  E.  stamp 80  333 

domes      , 48  194 

fusible  plugs    113  430 

Locomotive  type  boiler,  water  leg  and  door  frame  rings 8  13 

Longitudinal  joints    45  187-191 

joints  on  domes    , 48  194 

joints  of  h.r.t.  boilers  to  be  above  the  fire  line 45  189 

Lugs,  made  of  steel  plate 7  5 

Lugs,  to  support  h.r.t.  boilers    78  323—325 


136 


INDEX,    NEW   INSTALLATIONS    OF    POWER    BOILERS 


M  PAGB       PAB. 

Main  steam  pipe,  stop  valve  on 76  301-304 

Malleable   castings,    specifications  for 29  111—120 

Manhole    in    dome   heads 67  264 

openings,    minimum   sizes   of 65  258 

plates,    material   of    67  262 

reinforcement,    material    of    65  259 

reinforcement,  on  boiler  48  in.  diameter  or  over 65  260 

Manholes    65  258-264 

below  tubes,  h.r.t.  boiler -.  .  67  264 

below  tubes,  h.r.t.  boiler,  staying  of 54  218 

covers,  material  of    67  262 

covers,   when   plate   steel 7          5 

in.  a  dished  head   49  198 

frame,    riveting  of    65  260 

dftmne,  proportions  of 66  261 

^gaskets,    bearing    surface    of .' 67  263 

in  anj  fire  tube  boiler,  over  40  in.  diameter 67  264 

Manufacture   {See  specifications) 

Manufacturer's   stamp 79  332 

Manufacturer's   stamp,    not   to   be    covered 80  334 

Materials,   selection   of    7          1-13 

Maximum  allowable  working  pressure 

braced   and   stayed   surfaces : 49  199 

shells  of  power  boilers    43  179-180 

Methods   of  support    78  323-325 

Morison  furnaces    . 63  243-244 

Mud  drums,    material  of 8  10 

Huffier   on   safety  valves .*. 73  279 

N 

Non-return  stop  valves,   automatic 76  303 

Nozzles,   material  of    8  12 

Nozzles    and    fittings     76  299 

Number    of   gage    cocks 75  294 

Numbers,    serial    79  332 

O 

OQ    flanged    construction 8  13 

Openings,  threaded  to  be  reinforced 68  268 

Outside  screw  and  yoke  valves,  on  steam  pip? 76  301 

Outside  screw  and  yoke  valves,  on  water  column 75  293 

P 

Pins  in  braces,  diameter  of 55  223 

Pipes,  bottom  blow-off  and  fittings,  power  boilers 77  308 

feed   and    fittings    77  314-317 

in  steam  space    75  290 

main  steam,  valves  on    76  301 

or  nipple,  number  of  threads  into  fitting 76  300 

or  nipple,  number  of  threads  into  fitting,  table 68  268 

surface    blow-off    and    fittings 76  307 

threads,    minimum    number    of 68  268 

water  column,   and  fittings 78  320 

Piping,    feed    77  314-318 

Pitch  of  rivets    44  182 

of   rivets    95  410 

stay-bolts 50  199 

st-y-bolts,    table    51  203 

stay  tubes   59  233 


INDEX,    NEW   INSTALLATIONS    OF   POWER    BOILERS 


137 


PAGE  PAR. 

Planing   edges    of   plates 65  257 

Plate,    steel,    specifications    for 11  23-  39 

Plates,  thickness,  in  shell  or  dome  after  flanging 9  18 

minimum   thickness    of    in    a    boiler 9  17-  20 

minimum  thickness   of  stayed  flat   surface 49  199 

Plugs,    fusible    113  428-430 

Pressure,  allowed  on  shell  or  drum,  formula  for,  power  boilers 43  180 

maximum  allowable  working,  on  flat  surfaces,  power  boilers 49  199 

maximum  allowable  working,  on  shells,  power  boilers 43  179-180 

parts  over  2  in.,  material  of 8  9 

parts   of   superheaters,    material   of 8  11 

Pump,  to  supply  feed  water 78  318 

Purves    furnaces     G3  243 

R 

Reinforced  threaded  openings  in  shell,  heads  or  drums 68  268 

Reservoirs,    on  steam  mains 76  305 

Rings,  waterleg  and  door  frame,  material  of 8  13 

Rivet  holes,   finish  and  removal  of  burrs 65  253—254 

iron,    specifications    for     31  121-138 

steel,    specifications    for    15  40-  62 

Riveted   joints    (See  joints) 

Riveting     65  253-256 

Rivets 

allowable  shearing  strength  of 8  16 

in  braces,    area   of 55  223 

in  shear  on  lugs  or  brackets 79  325 

in  shear   on   manhole   frames 65  260 

length  of  and  heads  for 65  255 

machine    driven     65  256 

material   of    8  8 

to  completely  fill  rivet  holes 65  255 

Rolling,  ends  of  shell  plates 45  191 

S 

Safety,   factor  of,   for   power  boilers 43  180 

Safety  valve 

blow-down   adjustment    74  281 

capacity,   method  of  checking    107  422-427 

connections,    power    boilers    73-74  276-278 

280 
289-290 

constructor     74  282-287 

discharge    capacity,    power   boilers 68  .270-274 

discharge    capacity,    table    of ' 70-72 

escape   pipe   for    73  278 

formula    for     107  421 

metliod    of    computing    and    checking 107  421-427 

muffler   on    73  279 

power   boilers    68  269-290 

required  on  boiler    68  269 

seats  of    69  272 

setting    of     68  271-281 

size   limits,    power   boilers 69  272 

stamping    of     69  273 

superheater     74  288-289 

test   of    73  275 

Saw-tooth  type  of  butt  and  double  strap  joint 103  417 

Screwed    stays,    supporting    of 54  219 

Seamless  tubes,   specifications  for 40  164-178 

Seats  of  safety  valves 69  272 

Sections   of  cast  iron,    to  be   tested 87  372 


138 


INDEX,    NEW    INSTALLATIONS    OF    POWER    BOILERS 


PAGH  PAB. 

Segment,   area  to  be  stayed    53  214-217 

of  head,   to  be   stayed 53  213 

method  of  determining  net  areas,  water  tube  boilers 53  215 

Segments,   table   of    106  420 

Selection  of  materials    7  1-  IS 

Serial  number 79  332 

Setting  of  safety  valves    68  271 

Settings,    power   boilers    78  323-328 

Setting  of  wet  bottom  power  boilers 79  326 

Shearing   strength   of  rivets ...  8  16 

Shell  or  drum,  longitudinal  joints  of 45  187-190 

Shell  or  drum,  to  determine  allowable  pressure  on,  new  boilers 43  180 

Shell  plate,  thickness  of 9  17-20 

Shut-off  valves  on  water  column  pipes 75  293 

Sizes   of   flanged   fittings,    tables 110-111 

Sling    stays    60  235-236 

Specifications  for  gray  iron  castings 26  95-110 

lap  welded  and  seamless  boiler  tubes 40  164-178 

malleable    castings     29  111-120 

plate   steel 11  23-  39 

refined    wrought    iron   bars 37  151-153 

rivet    iron     31  121-138 

rivet    steel    15  40-  62 

stay  bolt  iron   34  139-150 

stay  bolt  steel   19  63 

steel  bars   19  64-76 

steel    castings     22  77-  94 

Stamping  boilers  A.S.M.E.  std 79  332 

Stamps,  A.S.M.E.  std.,  location  of 80  333 

Stamps,   not  to  be  covered  by  insulation 80  334 

Stamps,  to  be  visible  on  shell  plates,  furnace  sheets  and  heads 79  331 

Stay  bolted  surface,  to  compute  allowable  pressure  on 49  199 

Stay  bolts 

adjacent  to  edges  of  stay-bolted  surface 51  205 

adjacent  to  furnace  door  or  other  opening 52  206 

adjacent  to  furnace  joint,   v.t.  boiler 60  238 

diameter   of,    how    measured 52  208 

ends  of 50  200-202 

holes  for    52  210 

iron,  specifications  for   34  139-150 

material    of    7  7 

maximum    allowable    stress    on 54  220 

pitch   of    49  199-204 

steel,    specifications   for    19  63 

tables    of    allowable    load    on 104  418-419 

Stayed   and  braced   surfaces 49  199-233 

Stayed   flat   surface    49  199 

Staying  heads    55  222 

heads  h.r.t.  boiler  36  in.  or  less  diameter 56  225-229 

dished  heads    , 49  196 

furnaces     52  212 

segments   of  heads    53  213 

segments  of  he*ds  with  manhole  opening 54  218 

Stay-rods,  ends  riveted  over,  to  be  supported 54  219 

Stay-tubes     58  232-233 

Stays,    crown   bars  and   girders 58  230 

cross   sectional   area   in   calculating 52  209 

diagonal  and  gusset,   stresses  in 54  221-222 

224 

maximum   allowable    stress    54  220 

sling     60  235-236 


INDEX,    NEW   INSTALLATIONS    OF   POWER   BOILERS 


139 


PAGB  PAR. 

Stays,   tables   of    allowable    load   on 104  418-419 

screwed,    supporting   of 54  219 

upset   for   threading 52  211 

and  stay-bolts,   allowable  stress  on 54  220 

and  stay-bolts,   table  of   allowable   stress  on 104  418-419 

Steam  gage   and  connections,   power  boilers 75  296—298 

maias     76  305 

mains,    reservoirs   on    76  305 

outlets     76  301 

Steel   bars,    for  boiler  parts 7  6 

castings,    specifications    for    22  77-  94 

crushing   strength   of  plate 8  15 

for  rivets,   specifications  for 15  40—  62 

for  stay-bolts,   specifications  for    19  63 

plates   exposed   to   fire 7  2 

plates  when  firebox   quality  not  specified 7  3 

plates,    shearing   strength  of 8  16 

stays    and    stay-bolts     49  199-212 

wrought  or  cast,  for  boiler  and  superheater  parts 8  11 

plate,    crushing    strength    of 8  15 

plate,    specifications  for    11  23-  39 

plate,    tensile    strength    of 8  14 

Stop   valves    (See   valves) 

Straps,    butt,    of   equal   width 103  417 

Straps,    butt,    saw-tooth    103  417 

Superheater    drains    76  306 

safety    valve    on    74  288-289 

tubes   and   nipples    64  251-252 

Superheaters  and  mountings,  material  for 8  11-  12 

Support,    methods   of,    for   boilers 78  323-326 

Support,    of   stays,   ends   riveted   over 54  219 

Surface   blow-off    76  307 

Suspended  type   of  setting   h.r.t.  boilers 78  324 

T 

Table  of  angles  for  staying  heads 56  225 

constants  for  pitch   of  stay  tubes 59  233 

discharge  capacities  of  spring-loaded  safety  valves 69-72 

flange   fittings,    standard    110 

flange  fittings,   extra  heavy Ill 

maximum   allowable   pitch   of  stay-bolts,    ends   riveted 51  204 

maximum  allowable  stresses  for  stays  and  stay-bolts 54  220 

minimum  pipe   threads   for  boiler   connections 68  268 

net    areas    of    segments 106  420 

round  braces  or  stay  rods,   allowable  loads 105  419 

stay-bolts,   allowable  loads,    12   threads  per  inch 104  418 

stay-bolts,   allowable  loads,   10   threads   per  inch 105  418 

thickness   of  butt    straps    9  19 

Tensile   strength   of  steel  plate 8  14 

Test,   hydrostatic,    of   power  boilers 79  329-330 

of  safety  valve,   power  boilers 73  275 

of   steam    gage    75  298 

gage,   connection    for    75  298 

Thickness  of  corrugated  or  ribbed   furnace 64  244 

required  for  boiler  plates 9  17 

required  for  butt  straps 9  19 

required  for  dome  plates  after  flanging 9  18 

required  for  shell  plates 9  18 

required  for  tube  sheet?,    9  20 

required  for  tubes    10  21-  22 

Threaded   openings    68  268 


140 


INDEX,    NEW    INSTALLATIONS    OF    POWER    BOILERS 


PAGB          PAK. 

Threads,  pipe  or  nipple  into  fitting 76  300 

Threads,  table    68  268 

Tin,    for   fusible  plugs 113  428 

Truncated  cones,   maximum  allowable  working  pressure  on 58  231 

Tube  ends,   fire  tube  boiler 64  250 

ends,  water  tube  boilers  and  superheaters 64  252 

for   fusible    plug 113  429 

heads,  staying  upper  segments  of,  by  steel  angles 56  225-229 

heads,  of  water  tube  boilers 53  215 

holes  and  ends    64  248-252 

holes,    diagonal,    in   shell   or   drum 47  193 

holes  in   shell  or    drum 46  192 

holes,    sharp  edges  to   be  removed 64  249 

sheets  of  combustion  chambers    59  234 

sheets,    minimum    thickness    of 9        20 

sheets,  space  allowed  unstayed  between  tubes  and  between  tubes  and  shell  53  216 

Tubes  for  fire-tube  boilers,  thicknesses  of 10        22 

for  water  tube  boilers,   thicknesses  of 10        21 

lapwelded   and   seamless,    specifications   for 40  164-178 

required    thickness     10        21—  22 

stay     58  232-233 

Y 

Valves,    automatic,   on  water  glass 75  292 

automatic  non-return  stop    76  303 

extra   heavy,    on    bottom   blow-off 77  311 

extra  heavy,    on  main   steam  pipe 76  302 

globe,  not  to  be  used  on  blow-off 77  308 

globe,    on   feed   pipe 77  314 

'  on  bottom  blow-off    77  308-311 

on   every  steam   outlet 76  301 

on  feed  pipe    77  317 

on    Lamphrey    fronts    78  319 

outside   screw  and   yoke   type,    on    steam  pipes 76  301 

outside  screw  and  yoke  type,   on  water  column 75  293 

safety   (See  safety  valves) 

stop     76  301-304 

stop,    dra-ins  for    76  303-304 

Vertical  boilers,   furnaces  of 60  237-238 

fire-tube  boiler,   manhole  in 67  264 

fire-tube  boiler,  waterleg  and  door  frame  ring 8        13 

W 

Washout    holes,    power    boilers 67  265-267 

Water  column  and  connections,   power  "boilers 78  320-322 

column  and  connections,   power  boilers 75  295 

glass  and  gage  cocks,   location  of,   power  boilers '. 75  291—292 

glass,    automatic    valves    not    allowed 75  292 

tube  boilers,   cast  iron  for  headers  of 64  246 

tube  boilers,   flaring  of  tube  ends 64  251 

tube  boilers,   thicknesses  of   tubes  of 10        21 

tube  boilers,   wrought  or  cast  steel,   parts   of 8          9 

Waterleg   rings,    material    of 8        13 

Welded  joints    45  186 

Welded    stays     52  209 

Wet  bottom  boilers,   height  from  floor  line 79  326 

Working  pressure,    maximum   allowable,    power  boilers 43  179-180 

Wrought   iron    (See  iron) 
Wrought   steel    (See   RfpoT) 


INDEX  TO  RULES  FOR  NEW  INSTALLA- 
TIONS OF  HEATING  BOILERS 


PAGE 


PAK. 


Access  and  firing  doors,   heating  boilers 86  370 

Allowable  working  pressure,   heating  boilers 81  338-340 

Allowable  working  pressure,  existing  installations,  steam  heating  boilers.  .  90  383 

Altitude    gages     85  362 

Area,  grate  surface,  table  to  determine  size  of  safety  valves 84  356 

B 

Blow-off   cock,    heating   boilers 86  364 

Blow-off  piping,   heating  boilers 86  364 

Boiler  wet  bottom,  distance  from  floor  line,  heating  boiler 86  369 

Butt  and  double-strap  joint 

double    riveted     97  413 

triple    riveted    98  414 

quadruple  riveted    99  415 

quintuple    riveted    101  416 

0 

Cast  iron  boiler 

hydrostatic  pressure  test   of .  . 87  372 

maximum  pressure  allowed  on 87  374 

section  to  be  tested 87  372 

Connections,    flanged    82  346 

Crushing  strength  applied  to  joints 95  410 

D 

Damper  regulator,  connected  to  steam  space 86  365 

Diameter  of  fusible  metal  in  fusible  plug 113  429 

Door,   access  and  firing,  minimum  size  of,   heating  boilers 86  370 

Down-draft  boilers,   safety  valves   for 85  359 

E 

Efficiency  of  riveted  joints,  to  calculate 95-103  410-417 

Escape  pipe,  from  safety  valve,  heating  boilers 83  355 

Existing   installations,    steam   heating   boilers 90  383 

Extra  thick  tube,  for  fusible  plug 113  429 

F 

Factors  of  safety  for  steel  heating  boilers 81  340 

Fittings   and  appliances,   heating  boilers 86  364-368 

Flange  fittings,   tables  of  sizes  of 110-111 

Flange    steel,    for  heating  boilers 81  337 

Flanged   connections,   heating  boilers '.  .  .  82  '  346 

Fusible   plugs    113  428-430 

Fusible   plugs,    location    of 113  430 

141 


142 


INDEX,    NEW    INSTALLATIONS    OF    HEATING    BOILERS 


PAGH  FAB. 

Gage,    altitude    85  362 

cocks,    heating   boilers    86  367 

steam  and  connections,   heating  boilers 85  361 

water  glass,    heating   boilers 86  366 

Gas  fired  boilers,   safety  valves   for 85  360 

Grate  surface,  table  of,  for  safety  valves 84  358 

H 

Heating  boilers 81  335-377 

Heating  boilers,  to  which  the  rules  of  power  boilers  shall  apply 81  335 

Holes  for  wash-out,  heating  boilers 82  345 

Hot  water  boilers 81  335-377 

Hydrostatic  pressure  test 

heating   boilers 87  372-374 

on  sections  of  cast  iron  boiler 87  372 

I 

Inspection   at   shop,   heating  boilers 87  375 

J 

Joints,  butt  and  double  strap,  double  riveted,  example  of 97  413 

butt  and  double  strap,  triple  riveted,  example  of 98  414 

butt  and  double  strap,  quadruple  riveted,  example  of 99  415 

butt  and  double  strap,   quintuple  riveted,  example  of 101  416 

efficiency  of  detailed  methods  of  calculation 95  410 

heating   boilers    82  341-344 

lap,  double  riveted,  longitudinal  or  circumferential,  example  of 96  412 

lap  riveted,  allowed  on  shell  or  drum  not  over  36  in.  diameter 45  188 

lap  single  riveted,  longitudinal  or  circumferential,  example  of 96  411 

longitudinal  lap  joints  on  heating  boilers 82  341 

longitudinal  of  h.r.t.  boiler  to  be  above  the  fire  line,  heating  boilers.  .  86  371 

longitudinal,   maximum  length   of,   heating  boilers 82  342 

protection  of    82  344 

L 
Lap  joints 

length    of,    heating  boilers 82  342 

longitudinal  or   circumferential,   single   riveted 96  411 

longitudinal  or  circumferential,   double  riveted 96  412 

longitudinal   hot   water   boilers 82  343 

longitudinal,    steam    heating   boilers.  .  . 82  341 

Location   of   fusible   plugs 113  430 

Longitudinal  joints,    steam   heating  boilers 82  341 

Longitudinal  joints,  hot  water  boilers .'..,  82  343 

Longitudinal  joints  of  h.r.t.  boilers  to  be  above  the  fire  line 86  371 

Low  pressure  steam  boiler 81  335-377 

M 

Manufacturer's  name,   heating  boilers 87  377 

Materials,    selection   of,    for   heating  boilers 81  335-337 

Maximum   allowable   working  pressure,   heating  boilers 81  338-340 

N 

Name,  manufacturer's,  on  heating  boilers.  . 87  377 


INDEX,    NEW   INSTALLATIONS   OF    HEATING   BOILERS  148 
0 

PAGH  PAR. 

Oil-fired  boilers,    safety   valves  for .'. . .  85  360 

Openings,   flanged  connections,  heating  boilers 82  346 

P 

Pipes,  bottom  blow-off  and  fittings,  heating  boilers 86  364 

Pitch  of   rivets 95  410 

Plugs,    fusible    < 113  428-430 

Power  boiler  requirements  for  certain  heating  boilers 81  335 

Pressure,    allowed   on   cast   iron  boilers 81  338 

maximum  allowable  working,  old  boilers,  steam  heating 90  383 

maximum   allowable   working,    heating  boilers 81  338-340 

Protection   of  joints    .  . , 82  344 

R 

Regulators,    damper    86  365 

Relief  valves  for  hot  water  boilers 83  349-350 

Riveted   joints    (See   joints) 

S 

Safety,  factor  of,  for  steel  plate  heating  boilers 81  340 

Safety   valve   connections,    heating   boilers 83  347 

Safety  valve 

construction,   heating  boilers    84  356-358 

escape   pipe   for  heating   boilers 83  355 

for   down    draft  boilers 85  359 

for  heating  boilers    83  347-360 

for  oil  and  gas  fired  boilers 85  360 

for  formula  for  heating  boilers 83-84  351-358 

required    on    heating    boilers 83  348 

seats   of,    heating  boilers 84  357 

setting   of,   existing   installations,   heating  boilers 83  348 

size    limits,    heating   boilers 83  351 

stamping   of   heating  boilers 84  357 

table  of,    for  heating  boilers 84  356 

Saw-tooth  type  of  butt  and  double  strap  joint 103  417 

Setting  of  safety  valves,  existing  installations,  heating  boilers 83  348 

Settings,    heating   boilers    86  369-371 

Setting   of  wet  bottom  heating  boilers 86  369 

Shop  inspection  of  heating  boilers 87  375 

Sizes  of  flanged  fittings,   tables 110-111 

Specifications  for  material,   heating  boilers 81  336 

Steam  gage  and  connections,    heating  boilers 85  361 

Steam  heating  boilers,    existing  installations 90  383-384 

Steel  plate  heating  boilers 81  335-340 

Straps,  butt,  of  equal  width 103  417 

Straps,   butt,   saw-tooth    103  417 

T 

Table   of   flange   fittings,    standard 110 

of  flange   fittings,    extra   heavy Ill 

of  sizes  of  safety  valves,   heating  boilers 84  358 

of  stay-bolts,  allowable  loads,   12  threads  per  inch 104  418 

of  stay-bolts,    allowable  loads,    10  threads  per  inch 105  418 

Test,    hydrostatic,    of   heating  boilers 87  372-375 

Thermometers  on  hot  water  boilers 86  363 

Threads,    table 68  268 


144  INDEX,    NEW    INSTALLATIONS    OF    HEATING    BOILERS 

PAGE  PAB. 

Tin,    for   fusible   plugs 113  428 

Tube   for   fusible   piug 113  429 

V 

Valves,    safety    (See   safety  valves) 

W 

Washout   holes,   hot   water  boilers 82  345 

Water  column  and  connections,  heating  boilers 86  368 

glasses,    heating  boilers 86  366 

relief  valves  for  hot  water  boilers 83  349-350 

Wet  bottom  boilers,  height  from  floor  line,  heating  boilers 86  369 

Working  pressure,  maximum  allowable,  steam  and  hot  water  boilers 81  338-340 


INDEX  TO  RULES  FOR  EXISTING 
INSTALLATIONS 


PAGE 


PAR. 


Additional  safety  valves,   existing   installations 91  393 

Age  limit  for  lap  seam  boilers 89  380 

Allowable  working  pressure,   existing  installations 89  378-384 

B 

Blow-off    cock,    existing    installations 93  401-403 

Blow-off   piping,    existing   installations 93  401-405 

B.t.u.'  of    various   fuels 109  427 

Butt   and  double-strap  joint 

double    riveted 97  413 

triple    riveted    98  414 

quadruple    riveted     99  415 

quintuple    riveted    101  416 

0 

Capacity  of  safety  valves,   examples  of  checking 108  423-426 

Capacity  of  safety  valves,  method  of  checking  existing  installations 91  391-392 

Cast  iron  headers,  maximum  pressure  allowed  on,  existing  installations.  .  .  90  382 

Check  valve   on  feed-pipe,   existing  installations 93  406 

Checking  safety  valve  capacity,  method  of,  existing  installations 91  391-392 

Cock    (See  valves,   gage  cocks,  blow-off  cocks) 

Crushing  strength  of  steel  plate,  existing  installations 90  387 

Crushing  strength,    applied  to   joints 95  410 

D 

Damper  regulator  connected  to  water  column,  existing  installations 92  397 

Diameter  of  fusible  metal  in  fusible  plug 113  429 

Diameter  of  rivet  holes,   old  boilers 90  388 

Drains  from  stop  valves,  existing  installations 92  400 

E 

Efficiency   of  riveted  joints,   to   calculate 95-103  410-417. 

Escape  pipe,  from  safety  valve,   existing  installations 91  394 

Exfra  thick  tube,   for  fusible  plug 113  429 

F 

Factors  of  safety  for  existing  boilers. 89  379 

Factors  of  safety  for  second-hand  boilers 90  381 

Feed  piping,    existing  installations 93  406 

Fittings    and   appliances,    existing   installations 92  395-407 

Fuels,   heats  of  combustion   of 109  427 

Fusible    plugs     113  428-430 

Fusible  plugs,   location  of    113  430 

145 


146 


INDEX    TO    RULES    FOR    EXISTING    INSTALLATIONS 


PAGE  PAR. 


Gage    cocks,    existing    installations 92  396 

Gage,  steam  and  connections,  existing  installations 92  398 

Gage,    water  glass,    existing   installations 92  395-396 

H 

Headers,    cast   iron,    existing  installations 90  382 

Heating   boilers,    existing   installations 90  383-384 

Heat  of  combustion  of  various  fuels 109  427 

Hydrostatic  pressure  test,    old  boilers , 93  408^409 

I 

Iron  wrought,  tensile  strength,  existing  installations 90  385 

J 

Joints,  butt  and  double  strap,  double  riveted,  example  of 97  413 

butt  and  double  strap,  triple  riveted,  example  of 98  414 

butt  and  double  strap,  quadruple  riveted,  example  of 99  415 

butt  and  double  strap,  quintuple  riveted,  example  of 101  416 

efficiency  of,   detailed  methods   of  calculation 95  4lu 

existing  boilers    89  380 

lap,  double  riveted,  longitudinal  or  circumferential,  example  of 96  412 

lap    crack     90  384 

lap  riveted,  allowed  on  shell  or  drum  not  over  36  in.  diameter 45  188 

lap  single  riveted,  longitudinal  or  circumferential,  example  of 96  411 

L 

Lamphrey  fronts,   valves   on   existing  installations 93  407 

Lap  joint   crack    90  384 

joints,   longitudinal   or   circumferential,    single    riveted 96  411 

joints,  longitudinal  or  circumferential,  double   riveted 96  412 

joints,   longitudinal  lap  crack 90  384 

Location    of  fusible   plugs 113  430 

Longitudinal   joints,    lap    crack 90  384 

M 

Maximum  allowable  working  pressure,    existing  boilers 89  378-384 

Mud  drums,   maximum  allowable  working  pressure 90  382 

P 

Pipes,  bottom  blow-off  and  fittings,   existing  installations 93  401-405 

Pitch  of  rivets    95  410 

Plugs,    fusible    113  428-430 

Pressure,  allowed  on  shell  or  drum,  formula  for  existing  installations 89  378 

Pressure,  maximum  allowable  working,    old  boilers 89  378-384 

R 

Riveted  joints    (See  joints) 

Rivets,   allowable   shearing   strength   of,    existing   installations 90  386 

Rivets,    existing   boilers,    diameter    of 90  388 

S 

Safety  valve,   test  of  existing   installations. 91  391 

Saw-tooth  type  of  butt  and  double  strap  joint 103  417 

Second  hand  boilers 90  381 

Setting  of  safety  valves,  existing   installations 91  390 

••'••' 


INDEX    TO    RULES    FOR    EXISTING    INSTALLATIONS 


147 


PAGB  PAR. 

Shearing   strength   of   rivets,   existing   installations 90  386 

Shell  or  drum,  to  determine  allowable  pressure  on,  existing  boilers 89  378 

Steam  gage   and   connections,   existing  installations 92  398 

Steam    outlets,    existing    installations 92  399 

Steel,    tensile   strength   of,   existing   installations 90  385 

Stop   valves    (See   valves) 

T 

Table  of  sizes  of  rivets,   existing  boilers 90  388 

Tensile  strength  of  steel  or  wrought  iron,  existing,  installations 90  385 

Test,    hydrostatic,    existing    installations 93  408-409 

Test,   of  safety  valve,  existing  installations. 91  391 

Tin,    for  fusible   plugs 113  428 

Tube   for   fusible   plug 113  429 

V 

Valves,   on  bottom  blow-off,  existing   installations 93  401-403 

on   feed   pipe,    existing    installations 93  406 

on   Lamphrey   fronts,    existing   installations 93  407 

safety    (See   safety   valves) 

stop,  existing  installations    92  399 

stop,    existing  installations,    drains 92  400 

w 

Water  column   and   connections,   existing   installations 92  397 

Water   glasses,    existing    installations 92  395 

Working  pressure,   maximum  allowable,  existing   installations 89  378—384 


788145 


Engineering 
Library 


UNIVERSITY  OF  CALIFORNIA  LIBRARY 


